RESPONSE TO COMMENTS
Amendments to the Public Health and Environmental
Radiation Protection Standards for Yucca Mountain, Nevada
40 CFR Part 197
Final Rule
September 2008
Office of Radiation and Indoor Air
U.S. Environmental Protection Agency
Washington, D.C.

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Introduction
The Environmental Protection Agency (EPA) has promulgated amendments to its public
health and safety standards for radioactive material stored or disposed of in the potential
repository at Yucca Mountain, Nevada (40 CFR Part 197). Section 801 of the Energy
Policy Act of 1992 [(EnPA, Public Law 102-486, 42 U.S.C. § 10141 n. (1994)] directed
EPA to develop these standards. Section 801 of the EnPA also required EPA to contract
with the National Academy of Sciences (NAS) to conduct a study to provide findings and
recommendations on reasonable standards for protection of the public health and safety.
The health and safety standards promulgated by EPA are "based upon and consistent with"
the findings and recommendations of NAS in its 1995 report titled: "Technical Bases for
Yucca Mountain Standards"(NAS Report, Docket No. EPA-HQ-OAR-2005-0083-0076).
"Public comments reproduced in this document were taken from submittals to Docket No.
EPA-HQ-OAR-2005-0083 (in Regulations.gov) and records from public hearings. EPA is
solely responsible for the identification and categorization of comments. While we have
attempted to preserve original comments, in some cases, we may have combined or
paraphrased comments. However, we have not revised or corrected any quoted comments
for readability or other reasons. Also, in reproducing oral testimony from public hearings,
EPA has relied upon the official transcript and has not changed any text. Where words
appear to have been transcribed incorrectly, EPA has consulted the whole of the testimony
to discern the intended meaning."
The Nuclear Regulatory Commission (NRC) will incorporate EPA's final standards into its
licensing regulations. The Department of Energy (DOE) must demonstrate compliance
with these standards based upon the license application it submitted to NRC on June ,
2008. The NRC will use its licensing regulations to determine whether DOE has
demonstrated compliance with standards prior to issuing the necessary authorization and
license to store or dispose of radioactive material at Yucca Mountain.
What is Yucca Mountain?
Yucca Mountain is the site of DOE's potential geologic repository designed for disposal
of spent nuclear fuel (SNF) and high-level radioactive waste (HLW). If approved, the
site would be the Nation's first geologic repository for disposal of this type of
radioactive waste.
The site is located in Nye County, Nevada, about 100 miles northwest of Las Vegas on
federally owned land on the western edge of DOE's Nevada Test Site (NTS). The
repository would be approximately 1,000 feet below the top of the mountain and 1,000
feet above the ground water.
The potential Yucca Mountain repository is above a large, deep source of fresh water
currently used as agricultural and drinking water. This water feeds a larger ground water
basin south of the site that has the potential to supply many people in the surrounding area.
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Background
SNF and HLW have been produced since the 1940s, mainly as a result of commercial
power production and defense activities. Since then, the proper disposal of these wastes
has been the responsibility of the Federal Government. The Nuclear Waste Policy Act of
1982 (NWPA, Public Law 97-425) formalized the current Federal program for the
disposal of SNF and HLW by:
(1)	directing EPA to set generally applicable environmental radiation protection
standards based upon authority established under other laws;
(2)	requiring NRC to implement our standards by incorporating them into its
licensing requirements for SNF and HLW repositories; and
(3).	making DOE responsible for siting, building, and operating an underground
geologic repository for the disposal of SNF and HLW.
In 1985, EPA established generic standards for the management, storage, and disposal of
SNF, HLW, and transuranic (TRU) radioactive waste (see 40 CFR Part 191, 50 FR 38066,
September 19, 1985), which apply to any facilities for the storage or disposal of these
wastes, including (at the time) Yucca Mountain. In 1987, the U.S. Court of Appeals for
the First Circuit remanded the disposal standards in 40 CFR Part 191 (NRDC v. EPA, 824
F.2d 1258 (1st Cir. 1987)). As discussed below, EPA later amended and reissued these
standards to address issues that the court raised.
Also in 1987, the Nuclear Waste Policy Amendments Act (NWPAA, Public Law
100-203) amended the NWPA by, among other actions, selecting Yucca Mountain,
Nevada, as the only potential site that DOE should characterize for a long-term
geologic repository. EPA issued the amended 40 CFR Part 191 disposal standards,
which addressed the judicial remand, on December 20, 1993 (58 FR 66398).
In October 1992, the Waste Isolation Pilot Plant Land Withdrawal Act (WIPP LWA,
Public Law 102-579) and the EnPA became law. These statutes changed EPA's
obligations concerning radiation standards for the Yucca Mountain candidate disposal
system. The WIPP LWA:
(1)	reinstated the 40 CFR Part 191 disposal standards, except those portions
that were the specific subject of the remand by the First Circuit;
(2)	required us to issue standards to replace the portion of the challenged standards
remanded by the court; and
(3)	exempted the Yucca Mountain site from the 40 CFR Part 191 disposal
standards.
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The EnPA gave EPA new authority described in the first paragraph of this document, but
continued the general Federal agency responsibilities laid out in the NWPA. Thus, NRC
will issue implementing regulations for our amendments to the standards. The NRC then
will determine whether DOE, based upon its license application, has complied with the
standards and whether to issue a construction authorization and a license for Yucca
Mountain. The NRC will require DOE to comply with all of the applicable provisions of
40 CFR Part 197 before authorizing DOE to construct the repository and receive
radioactive material on the Yucca Mountain site.
In June 2001, we issued the public health and safety radiation standards for Yucca
Mountain, 40 CFR Part 197. The State of Nevada, the Natural Resources Defense
Council (NRDC), and several other environmental and public interest groups challenged
several aspects of our final standards in the Court of Appeals for District of Columbia
Circuit on the grounds that they were insufficiently protective and had not been
adequately justified. In July 2004, the U.S. Court of Appeals for the District of Columbia
Circuit ruled that the 10,000-year compliance period was not consistent with the NAS
recommendation "that the compliance assessment be conducted for the time when the
greatest risk occurs, within the limits imposed by long-term stability of the geologic
environment (NAS Report p. 7). The amendments that are the subject of comments in this
document are mainly in response to the Court ruling. In response to the Court's ruling, we
proposed amendments to the standards in August 2005. We have finalized these
amendments based, in part, upon the consideration of the public comments included in
this document.
Response to Comments
We held a 90-day public comment period for the proposed amendments to 40 CFR Part 197
from August 22, 2005 through November 21, 2005. Overall, we received about 2550 sets
of comments that amounted to about 3000 pages of comments and 1100 pages of
attachments. The large majority of these were in mass mailings, so counting each of the
mass mailing campaigns as one "submittal," there were about 300 individual submittals. In
addition, we received comment during oral testimony in public hearings in Amargosa
Valley, NV; Las Vegas, NV; and Washington, DC. Comments received on the proposal
were categorized according to topics. While EPA has cross-referenced related topics where
possible, it has not done so in every instance. The entire document should be considered as
a whole, for it collectively reflects EPA's consideration of public comments. While we
have attempted to preserve original comments, in some cases, we may have combined or
paraphrased comments.
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This document addresses comments received on the 2005 proposed amendments to the
radiation protection standards for Yucca Mountain by summarizing the views expressed by
commenters and presenting EPA's response to the comments. All comments received
during the public comment period and the public hearings have been fully considered.
Some comments were received after the close of the public comment period on November
21, 2005. However, these comments were still considered. We have addressed all
substantive comments, both written and oral. Responding to comments was difficult in
some cases because certain comments did not articulate specific concerns, did not suggest
concrete alternatives, or did not substantiate the position advocated.
Copies of all comments submitted to EPA regarding the proposed certification decision
can be found in the official docket, designated EPA-HQ-OAR-2005-0083, at
www.regulations.gov. Each comment is identified by a unique number. Appendix A of
this document correlates these identification numbers to the docket numbers and name(s)
of the commenter. Appendix A also identifies the people who testified at the public
hearings and the corresponding comment numbers. A list of acronyms and the terms
they represent are in Appendix B.
The docket, EPA-HQ-OAR-2005-0083, is located in the Docket public reading room,
which is located in the EPA Docket Center, Room 3334 (202-566-1742) in the EPA West
Building, located at 1301 Constitution Ave., NW, Washington, D.C. The Docket is open to
the public on all federal government work days from 8:30 a.m. to 4:30 p.m.. As provided
in 40 CFR Part 2, a reasonable fee may be charged for photocopying docket materials. We
also have placed an informational docket in the Lied Library at the University of Nevada-
Las Vegas, Research and Information Desk, Government Documents Section (702-895-
2200). Hours vary based upon the academic calendar, so we suggest that you call ahead to
be certain that the library will be open at the time you wish to visit (for a recorded message,
call 702-895-2255) or go to http://library.nevada.edu/about/hours.html.
You may also inspect the informational docket at the Public Library in Amargosa Valley,
Nevada (phone 775-372-5340) or go to http://www.avnv.net/library.html. As of this date,
the hours are M-W-F (9:00 a.m. - 5:00 p.m.) and Tuesday and Thursday (9:00 a.m. - 7:00
p.m.), and Saturday (9:00 a.m. - 1:00 p.m.).
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Yucca Mountain Standards	Resnonse to Comments
TABLE OF CONTENTS
Introduction
1.	General Comments	17
2.	Dose Limits	37
3.	Background Radiation	104
4.	Two-tiered Standards	132
5.	Risk Level	158
6.	Uncertainty	170
7.	Use the Mean or Median?	201
8.	Climate Change	220
9.	Intergenerational Equity	232
10.	Compliance Period	269
11.	Updating the Dose Methodology	286
12.	Ground-water Protection	291
13.	Tribal-related Comments	299
14.	Public Process, Interactions, and Outreach	307
15.	EPA's Role and Responsibilities	312
16.	FEPs and Screening Criteria	315
17.	Reasonable Expectation/Implementability	337
18.	Performance Assessment	353
19.	Human Intrusion	360
20 Comparison to WIPP is inappropriate	362
21. Miscellaneous Comments	367
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22.	EPA Should Balance the Risks from Storage with the Risk near Yucca Mountain... 378
23.	Add further criteria	381
24.	Legality of the Standards	384
25.	Out-of-the-scope of the Rulemaking or Non-comment	406
Appendix A: Index of Commenters
Appendix B: Acronyms
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Yucca Mountain Standards
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APPENDIX A
Index of Commenter
(The main Docket Number is EPA-HQ-OAR-2005-0083;
the number in the first column is the item number within the main docket,
e.g., 0003 is actually EPA-HQ-QAR-2005-0083-0003)
Docket Number
Commenter
0088
Gene Douglas
0089
Fred deSousa
0090
Stephen Hans
0091
Jeremiah (no other name)
0093
David Ottley
0094
Frank Albini
0095
K. Halac
0099
Nickolaus Leggett
0100
R.G. Dodge
0101
Manuel Bettencourt
0102
Bill Lawless
0103
Anonymous
0104
Alan Trunkey
0105
Faun Shillinglaw
0107
Alliance for Nuclear Accountability
0109
E. Spence
0110
R. Glenn Vawter
0111
Aviv Goldsmith
0112
K. Halac
0113
Faun Shillinglaw
0114
Louis H. Garner
0115
Melody Poison
0117
Robert Patterson-Rogers
0118
Tamara Downs-Schwei
0119
Nancy Ann Surma
0120
P. Christi
0121
Ann Collins
0122
Elizabeth Rogers
0123
Richard Lyons
0124
Shawn Wozniak
0125
Anonymous
0126
Bob Sutter (sample of mass mailing)
0127
John and Denise Madonna (sample of mass mailing)
0128
M. Lee
0129
Dennis F. Nester
0130
Ryan Kaplan
0131
Lou deBottari
0132
Unreadable (sample of mass mailing)
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0133
Stephen Schrems
0134
Anonymous
0135
Anonymous
0136
Anonymous
0137
Art Hanson
0138
Deborah Hunter
0139
Ezequiel Orona
0140
Marisa Dobson
0141
W.D. and Namsuk Mindock
0142
Stacy A. Miller
0143
Albert G. Cohen
0144
Robert Lincoln
0145
Anonymous
0146
Franklin J. Harte
0147
Joseph P. Mahon
0148
Anonymous
0149
Richard Zuckerman
0150
Edward Mainland (sample of mass mailing)
0151
Rosalie Bertell
0152
Cheryl Erb
0153
Donna Detweiler
0154
Janice Flanagan
0155
John Ullman
0156
Margaret Giancontieri
0157
Ella Craig
0158
Thomas Baldino
0159
Michael Moats
0160
Common Sense at the Nuclear Crossroads
0161
Anonymous
0162
Michael L. Cook
0163
Tammy (no last name)
0164
Valerie Heinonen
0165
Dot Sulock
0166
Janet Greenwald, Citizens for Alternatives to Radioactive

Dumping
0167
Susanne and Robert Vandenbosch
0168
Madonna Soctomah
0169
Nina Keller
0170
Ronald Kuhler
0171
Joy Reese
0172
Kathy Barnes
0173
Frank Perna
0174
Per Peterson, William Kastenberg, and Michael Corradini, UC-

Berkeley
0175
Rene Vivo
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Yucca Mountain Standards
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0176
Midgene Spatz
0177
Charles W. Morgan
0178
Martin Donohoe
0179
Ravi Grover
0180
Anonymous
0181
S.J. Gordon
0182
Seth Healy
0183
Susanne and Robert Vandenbosch
0184
Roberta Claypool
0185
Thomas Bjerstedt
0186
David C. Kocher
0187
Anonymous
0188
Anonymous
0189
Phoebe Mills
0190
Richard Lance Christie
0191
Deborah Baker
0192
Anonymous
0193
Daniel Walker, Californians for Safe, Clean, Efficient Nuclear
Power
0194
Nadine Hudes
0195
Tony Guzman
0196
J.E. Holmgren
0198
Sally Devlin
0199
Douglas Belyeu
0200
Walter Schwarz
0201
James E. Hopf
0202
John Walton
0205
Senators Reid and Ensign
0207
Rory Reid, Clark County, NV
0209
October 4, 2005 public hearing
(Las Vegas)
0209.1
Jacob Paz
0209.2
Judy Treichel
0209.3
Imogene Specks (phonetic)
0209.4
Joan Bingham
0209.5
Ian Zabarte
0209.6
Marta Adams, Senior Deputy Attorney General, Nevada
Attorney General's Office
0209.7
Robert Loux, Executive Director of the Agency for Nuclear
Projects, Office of the Governor of Nevada
0209.8
Robin Drew
0209.9
Dennis Beller
0209.10
Shannon Raborn, Senator Reid's office
0209.11
Irene Navis, Planning Manager, Clark County Nuclear Waste
Program
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0209.12
Jane Feldman, Southern Nevada Sierra Club
0209.13
Peggy Maze Johnson, Citizen Alert
0209.14
Judy Treichel, Nevada Nuclear Waste Task Force
0209.15
Mike Henderson, Congressman Gibbons' office
0209.16
Craig Walton, Nevada Center for Public Ethics
0209.17
Calvin Meyers
0210
October 5, 2005 public hearing
(Las Vegas)
0210.1
Micki Jay
0210.2
Fred Toomey
0210.3
Frank Perna
0210.4
Bill Vasconey
0210.5
Arthur Fillskawe (phoenetic)
0210.6
Ray Izen
0210.7
Kenny Anderson
0210.8
Frank Perna
0210.9
Bill Vasconey
0210.10
Unidentified
0211
October 6, 2005 public hearing
(Las Vegas)
0211.1
Mike Bauffman, Lincoln County
0211.2
Charles Taylor
0211.3
Charlotte Omahandro
0211.4
Michael Sherwood
0211.5
John Snyder
0211.6
Lowell Watkins, Democratic Central Committee in Nye County
0211.7
Richie DeClever
0211.8
David Cherry, Congresswoman Shelley Berkley's office
0211.9
Gigi Cotron
0211.10
Joshua Abbey
0211.11
Judy Treichel, Nevada Nuclear Waste Task Force
0211.12
Unidentified speaker
0212
Donna L. Antoucci
0213
M. Long
0214
Jacob D. Paz
0215
Richard S. Denning and Christopher Orton
0216
Dan Shively
0217
James Bradford Ramsay and Grace D. Soderberg, National
Association of Regulatory Utility Commissioners
0218
Rebecca Rossof
0219
George T. Rowe, Chairman, Board of County Commissioners,
Lincoln County, NV
0220
Donna L. Antoucci
0221
Jeff Odendahl
0222
Robert R. Loux, Executive Director, Agency for Nuclear
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Yucca Mountain Standards
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Projects, Office of the Governor of Nevada (no comment; just
cover letter submitting 0224 and 0225)
0223
Anonymous
0226
The Main State of Nevada Comments — Robert R. Loux,
Executive Director, Agency for Nuclear Projects, Office of the
Governor of Nevada (98 pages)
0257
Judy Treichel, Nevada NuclearWaste Task Force
0258
Anonymous
0259
Anonymous
0260
Anonymous
0261
Anonymous
0262
Anonymous
0263
Anonymous
0264
Lake Barrett, L. Barrett Consulting
0265
Ellen Nakamura
0266
Dennis Bechtel
0267
Nancy Myers
0268
John E. Hadder and Tony Guzman, Citizen Alert
0269
Theodore Rockwell
0270
Jacob Paz, J&L Environmental Services
0271
Congresswoman Shelley Berkley
0272
Anonymous
0273
Anonymous
0274
Ernest Fuller
0275
Anonymous
0276
Robert Hal stead
0277
R. Wilkins
0288
Joseph Dent
0289
M. Lee Dazey
0293
Senators Reid and Ensign
0294
Rochelle Becker, Alliance for Nuclear Responsibility
0295-0296
Daniel Hirsch, Committee to Bridge the Gap
0297
G. Steven Rowe, Attorney General, State of Maine on behalf of
the States of Maine and Vermont
0298
Steven P. Kraft, Nuclear Energy Institute
0301
Jaya Tiwari
0302
Melissa Kemp, Public Citizen
0303
Robert J. Halstead
0304
Jim Hall
0305
Clara Stang
0306
Jennifer Olaranna Viereck, Healing Ourselves and Mother Earth
0307
Jeffery M. Skov
0308
Miriam Goodman
0309
Vernon J. Brechin
0310
Petition (sample of mass mailing of petitions)
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0311-0311.1
Geoffrey H. Fettus, Senior Project Attorney, Natural Resources
Defense Council
0312
Colleen Flanagan
0313
David Bodansky
0314-0314.1
Lois Chalmers, Institute for Energy and Environmental
Research
0315
White Pine County (Nevada) Nuclear Waste Project Office
0316
Video tape of Amargosa Valley roundtable
0317
Video tape of Las Vegas roundtable
0318
Cecily Jones
0319
Carol Dunphy
0320
Pat S. Kenoyer
0321
Marie L. Stuckler
0322
Rory Reid, Clark County (Nevada) Board of County
Commissioners
0323
Rosa Mary O'Donnell
0324
Kevin Kamps, Nuclear Information and Resource
Service/World Information Service on Energy
0325
Robert J. Halstead
0326
James D. Boyd, California Energy Commission
0327
Rory Reid, Clark County (Nevada) Board of County
Commissioners (same as 0322)
0328
John E. Hadder and Tony Guzman, Citizen Alert
0329
Jean Sule, Savannah River Site Citizens Advisory Board
0330
Steven P. Nesbit, Duke Power
0331
Judith H. Johnsrud, Radiation Committee, Sierra Club
0332
Margaret Fitzgerald
0333
Marian Disch
0334
Jane Edsall
0335
Ann White
0336
Mary (surname illegible)
0337
Kathleen Vonderhaar
0338
Mary Rhodes Buckler
0339
Mary F. Lattes
0340
Steven P. Nesbit, Duke Power
0341
Oscar B. Goodman, Mayor of the City of Las Vegas (Nevada)
0342
Rose A. Schuler
0343
Josephine Miklic
0344
Barbara Coughan
0345
Lois Dunphy
0346
J. Entu
0347
V. M. Schneider
0348
David Radcliff, New Community Project
0349
Lorraine Gold
0350
John Tanner
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0351
Lake Barrett, L. Barrett Consulting, LLC
0352
Paul M. Golan, U.S. Department of Energy
0353
Ronald Damele, Office of Eureka County (Nevada) Public
Works
0354
Joni Arends, Concerned Citizens for Nuclear Safety
0355
Wells Bain
0356
William D. Peterson
0357
Robert R. Loux, Executive Director, Agency for Nuclear
Projects, Office of the Governor of Nevada
0358
William D. Peterson
0359
Robert R. Loux, Executive Director, Agency for Nuclear
Projects, Office of the Governor of Nevada (duplicate of 0357)
0360
Jessica L Bacoch, Tribal Chairperson, Big Pine Paiute Tribe of
the Owens Valley
0361
Ronald Damele, Office of Eureka County (Nevada) Public
Works
0362/362.1
Robert R. Loux, Executive Director, Agency for Nuclear
Projects, Office of the Governor of Nevada
0363
Jessica L Bacoch, Tribal Chairperson, Big Pine Paiute Tribe of
the Owens Valley (duplicate of 0360)
0364
October 3, 2005 public hearing (Amargosa Valley)
0364.1
Jan Cameron
0364.2
Ken Garey
0365
Robert Loux, Executive Director, Agency for Nuclear Projects,
Office of the Governor of Nevada
0366
Chris Giovingo
0367
Roundtable discussion summaries
0367.1
Amargosa Valley roundtable
0367.2
Las Vegas roundtable
0368
October 11, 2005 public hearing (Washington, DC)
0368.1
Lois Gibbs, Center for Health, Environment, and Justice
0368.2
Robert Musil, Physicians for Social Responsibility
0368.3
Arjun Makhijani, Institute for Energy and Environmental
Research
0368.4
Judith Johnsrud, Sierra Club
0368.5
David Wright, Commissioner, South Carolina Public Service
Commission representing the National Association of
Regulatory Utility Commissioners
0368.6
Michelle Boyd, Public Citizen
0368.7
Carah Ong, Nuclear Age Peace Foundation
0368.8
Steve Kraft, Nuclear Energy Institute
0368.9
Jim Bridgeman, Alliance for Nuclear Accountability
0368.10
Navin Nayak, U.S. Public Interest Research Group
0368.11
Robert Meisenheimer, Savannah River Site's Citizens Advisory
Board
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0368.12
Angela Kelly, Peace Action
0368.13
Kevin Kamps, Nuclear Information and Resources Services
0368.14
Dave Hamilton, Sierra Club
0368.15
Dennis Nelson, Support and Education for Radiation Victims
0369
Robert R. Loux, Executive Director, Agency for Nuclear
Projects, Office of the Governor of Nevada
0371
Robert Artley
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APPENDIX B
Acronyms and Abbreviations
BEIR
Biological Effects of Ionizing Radiation
BID
background information document
CED
committed effective dose
CEDE
committed effective dose equivalent
CFR
Code of Federal Regulations
DOE
U.S. Department of Energy
DOE/VA
DOE's Yucca Mountain Viability Assessment
EIS
Environmental Impact Statement
EnPA
Energy Policy Act of 1992
EPA
U.S. Environmental Protection Agency
FEIS
Final Environmental Impact Statement
FEPs
features, events, and processes
FR
Federal Register
GCD
greater confinement disposal
HLW
high-level radioactive waste
HSK
Swiss Federal Nuclear Safety Inspectorate
IAEA
International Atomic Energy Agency
ICRP
International Commission on Radiological Protection
KASAM
Swedish National Council for Nuclear Waste
LLW
low-level radioactive waste
MCL
maximum contaminant level
mrem/yr
millirem per year
mSv/yr
millisievert per year
MTHM
metric tons of heavy metal
NAPA
National Academy of Public Administration
NAS
National Academy of Sciences
NCRP
National Council on Radiation Protection and Measurements
NEA
Nuclear Energy Agency
NEI
Nuclear Energy Institute
NRC
U.S. Nuclear Regulatory Commission
NRDC
Natural Resources Defense Council
NTS
Nevada Test Site
NTT A A
National Technology Transfer and Advancement Act
NWPA
Nuclear Waste Policy Act of 1982
NWPAA
Nuclear Waste Policy Amendments Act of 1987
OECD
Organization for Economic Cooperation and Development
OMB
Office of Management and Budget
RMEI
reasonably maximally exposed individual
SSI
Swedish Radiation Protection Authority
SNF
spent nuclear fuel
SR
site recommendation
TRU
transuranic
TSPA
total system performance assessment
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UK
U.S.C.
WIPP LWA
United Kingdom
United States Code
Waste Isolation Pilot Plant Land Withdrawal Act of 1992
Section 1 General Comments
ISSUE A: The post-KKOOO-vear limit was written to be sure that Yucca Mountain can
be licensed.
1.	If the Mountain can't meet the standards, the EPA should not be changing the rules so
the site can meet them. That is wrong. People there should not receive extra radiation.
(Comment 0105-4)
2.	If EPA wouldn't allow 350 mrem/yr in Superfund, I see no reason to allow it at Yucca
Mt. just so NRC can license it. It is pretty obvious that there is no way you could use your
initial standard of 15 mrem/yr. beyond 10,000 years, so you found another way to let NRC
license the repository by changing the use of the average (or mean) and using the median
instead... .Someday in the far future, somebody is going to look back at your decision here
and just sit and wonder why this was done. EPA will have to take the blame. I feel you are
collapsing under political pressure here, because the nuclear industry is so strong. The only
way new plants can be built is if the waste goes into a repository. But don't you see, what
they see as the answer to the waste problem, is a green light to build new plants and create
more radioactive waste. And how much more exposure will EPA allow?... .You can say
that all that is to be considered in this rulemaking is the new standard you propose - but the
total picture of all the ramifications of this must be considered - for if this standard is
accepted, it will allow the licensing of the repository - you know that. This is the turning
point. Make this decision with all the gravity it deserves. (Comment 0113-8)
3.	When EPA began to write its new rule for Yucca Mountain, the Agency was faced with
a choice - to pass or fail the repository project. One option would have been to write a
rule that would provide protection to the public and the environment, as is the Agency's
charge. However, EPA chose to provide the means for the site to be approved and licensed
and the repository to be built. Instead of joining the "save the dump" political effort, EPA
must abandon this proposal and release a new draft for comment that provides real
protection for public health and the environment for the dangerous lifetime of the waste.
(Comment 0130-4, 0195-4, and 0257-1)
4.	When EPA's proposed dose criterion at times beyond 10,000 years and the proposal to
use the median, rather than the mean, to assess compliance with that dose criterion, are
considered together, it is difficult not to conclude that EPA has developed a standard that is
intended to ensure that the Yucca Mountain facility will comply with the standard, i.e., that
EPA's proposed standards beyond 10,000 years were based in large part on projected doses
beyond 10,000 years. Indeed, this conclusion seems almost inescapable when EPA's
decision not to extend groundwater protection requirements in § 197.30 beyond 10,000
years, which is based on a weak argument with no technical merit, is considered . .. .there
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is nothing inherently wrong with developing a standard for Yucca Mountain that is
reasonably achievable. EPA has often taken this approach in developing other radiation
standards including, for example, standards for releases from uranium fuel-cycle facilities
(40 CFR Part 190), standards for management and disposal of uranium or thorium mill
tailings (40 CFR Part 192), standards for radioactivity in drinking water (40 CFR Part 141),
and standards for airborne emissions of radionuclides (40 CFR Part 61) . The uranium fuel-
cycle and drinking water standards probably are the best examples, because they were
based almost entirely on EPA's evaluations of what was reasonably achievable, rather than
a priori judgments about acceptable exposures, doses, or health risks to the public ...
(Comment 0186-13)
5.	What criteria was used for research and for what length of time & where was this
done and how were these values selected to arrive at your numbers? (Comment 0198-2)
6.	It's my opinion that the EPA's attempt to massage and change the standard is not an
effort to protect the public but to give to the federal government what they want.
(Comment 0209.4-1)
7.	We believe that EPA has created a standard at the behest of and in collusion with the
Department of Energy to fit DOE site-specific needs for licensing. (Comment 0209.6-6)
8.	It's no coincidence that EPA's proposed standard for the proposed 10,000 years —
10,000-year period allows radiation doses ten times higher than during the initial period at
a level far beyond what EPA, in its previous rule-making, said, quote, No regulatory body
will ever consider acceptable. The only possible reason for the use of the convoluted,
bifurcated standard is EPA's commitment to promulgate a standard that will make DOE's
life easier in the NRC licensing process.
When the Court vacated EPA's original Yucca Mountain rule in 2004 for, among
other things, limiting the period of compliance for just 10,000 years. The simplest and most
logical thing for EPA to do was to extend the same allowable dose for the first 10,000 years
for the entire life of the repository. Yet EPA rejected that solution out of hand. Why? As
these varied EPA representatives have themselves acknowledged in the meeting with
Nevada officials earlier this year, to do that would disqualify Yucca Mountain. And EPA
has been directed to assure that does not happen. Instead, EPA has produced a collusion
with DOE, a standard that just coincidentally allows exposure slightly higher than DOE's
most optimistic estimates of where the maximum releases for Yucca Mountain will be after
10,000 years. EPA has manufactured a standard tailored to fit the site, not to protect public
health and safety.
EPA's proposed rules are unacceptable in all counts. It flaunted the intent of the
Court, which was to ensure that Yucca Mountain be judged using credible science based on
the maximum expected risk to the human health and safety. Instead, EPA is transparently
and unethically acting to facilitate the Yucca Mountain licensing by literally stacking the
deck with unprecedented, irresponsible breaks from established regulatory and ethical
principles. In developing the proposed Yucca Mountain health and safety standards, EPA is
turning the standard-setting process on its head. Instead of designing a regulation to protect
the current and future generations by ensuring the proposed repository site is, in fact,
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capable of isolating the waste, EPA has worked hand in glove with DOE to design a
standard with a single objective in mind: That it will not disqualify the site. (Comment
0209.7-5)
9.	The EPA has obviously conformed the standard to meet the ability of the DOE to
achieve them. The ploy is so transparent it's laughable. The watchdog has lost his bite.
Indeed, he has lost his bark. (Comment 0209.12-3)
10.	Many experts and scientists argued that the EPA could not realistically develop a plan
that could ensure public safety past 10,000 years. Unfortunately, many underestimated the
extreme measures the proponents of this protect would take to ensure that the scientifically
flawed project continues. Instead of playing by the rules of the game, rules intended to
protect public safety, the DOE and the EPA have decided to simply change the game.
In its most shockingly disturbing ruling yet, the EPA decided that it was
scientifically reasonable to increase its radiation standard after 10,000 years from 15
millirems to 350 millirems. This means the EPA has determined that once the clock hits
10,000 and one day, it is completely reasonable for the radiation exposure to increase 23-
fold. I and my fellow Nevadans emphatically disagree.
The EPA has an obligation to protect public safety today, tomorrow, and in a
million years. It should not speculate that a standard which is not deemed safe today could
miraculously become a safe standard in the future. This decision was not based on any
measure of public safety and instead just continues to highlight the means the DOE will go
to in order to ensure that the Yucca Mountain Project continues. This recent rule just
reinforces the idea that when you don't like the rules, you change the game. (Comment
0209.15-1)
11.	Neither EPA's 40 C.F.R. Part 197 rulemaking (published in 2001) nor its current,
revised proposal are the product of its independent judgment about the health and safety of
the citizens of the United States. Like its predecessor, the proposed rule reflects the
wholesale adoption of standards pushed on EPA by DOE and its industry allies as
representing merely the standards that could be met by a repository at Yucca, not the
standards that would protect the public health and safety in fulfillment of EPA's statutory
responsibilities. As a result, the current proposal is not the product of reasoned
decisionmaking and does not constitute a public health-based standard, as required by the
Energy Policy Act of 1992. (Comment 0226-7)
12.	Changing the rules as you have apparently done by greatly increasing the dose limit
does nothing but convince people that the dump site is bad and that the government is just
playing games to make it seem like it is good. You can't with a straight face allow much
higher doses and pretend that you are being protective and meeting your responsibilities.
(Comment 262-1)
13.	The Environmental Protection Agency has a difficult and vital role in our country
delineated in its mission statement. It must turn away from political pressures inside and
outside the administration to develop rules for protection based on our best understanding
of the risks involved. While Citizen Alert would like to see more stringent standards, at the
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very least, [15 mrem/yr and ground-water protection] should be upheld through the period
of peak risk; otherwise, the integrity of the EPA will be undermined. How are we to know
when the EPA is developing a sound scientifically protective standard or just bending to
special interests. Relaxing the standard to accommodate greater uncertainties is not
justifiable, and outside of the responsibility of the EPA. The preamble contends that since
the results of performance assessment past 10,000 years are highly uncertain and that a
higher allowed dose limit is necessary to satisfy a "reasonable expectation" of the goals of
the standard. The REASONABLE EXPECTATION is that the EPA will act as an
independent agency and advance protection standards that do just that, "...protect human
health and the environment." It is not the role of the EPA to cater to the "needs" of the
Dept. of Energy (DOE) to have a standard that will a priori allow Yucca Mountain to be
licensed. (Comment 0268-11)
14.	Citizen Alert sees this proposed rule as a collusion with the DOE and the NRC as well
to write a standard that superficially complies with the Court of Appeals ruling, and
tailored to be within the DOE's calculated expected doses. Thus, in effect, the
Environmental Protection Agency is working on behalf of the DOE and nuclear industry,
and abandoning its charge "...to protect human health and the environment." (Comment
0268-13)
15.	EPA has cast sound science aside in favor of political expediency in the myopic pursuit
of Yucca Mountain. (Comment 0293-1)
16.	[CJontrary to the original intent of the Nuclear Waste Policy Act, this project has been
driven by commercial and political interests rather than sound science. Rather than abandon
a site that has failed to meet even minimal public health and safety requirements, the
Department of Energy (DOE) and other government agencies involved in the Yucca
Mountain Project have repeatedly bent or changed rules and fabricated data to forge ahead
with a project that is a grave threat to public health and the environment. The new public
health and environmental radiation protection standards perpetuate gross violations of
scientific, ethical and public health principles that consistently characterize the
government's conduct with respect to the Yucca Mountain Project. (Comment 0301-1)
17.	Rather than setting a stringent health-based standard that the Yucca Mountain site
should meet to be licensed, the EPA appears to be creating a "two-tiered standard," which
is intended to help get the repository approved and open for business. DOE has publicly
estimated radiation doses of 250 millirem/year at 200,000 to 300,000 years in the future, so
EPA now proposes a standard above that level. Such blatant disregard for scientific
objectivity and public health is very disturbing. (Comment 0301-4)
18.	As an affected resident, I found many of the arguments for the original 15 millirem
standard to be flawed and misleading. If a site-specific standard was being created, site-
specific needs of those other than the DOE should have been addressed. (Comment 0306-
3)
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19.	According to the DOE's own estimates, the maximum dose from the Yucca Mountain
site would be between 200 to 300 millirem per year several hundred thousand years from
now. With this rule, the EPA appears to be pandering to current political interests that wish
to see Yucca Mt. stuffed full of radionuclides no matter what the environmental cost, at the
expense of future generations. (Comment 0306-12)
20.	The EPA's original requirements for the final disposal of spent nuclear fuel and high-
level nuclear waste, specified in 40 CFR Part 191, called for a deep geological repository
which would contain the radioactive waste via geology alone. Since then the standards
have been altered to compensate for various geologic weaknesses as have been found in the
planned Yucca Mountain repository. The latest proposed rule change is just another
example of dealing with Yucca Mountain's weaknesses by fudging the containment
standards. The EPA should choose to back out of this dark hole and reset its course so as to
extend the present radiation protection standards for 100 times the presently specified
10,000 year period for any and all future SNF and high-level nuclear waste repositories.
(Comment 0309-6)
21.	EPA has proposed a rule that will allow the site to be licensed when instead the Agency
should be proposing standards that rely on the geology of the site. The federal government
submits that the engineered barriers will never leak during the first 10,000 years, and the
rest of the time the standards allow an unprecedented dose for which the models can
demonstrate compliance. (Comment 0311.1-1)
22.	EPA's proposal is a shoehorn designed to weaken the standards so that the geologically
unsuitable site can still be licensed, rather than requiring the site to meet public health and
environmental protection standards. If the Yucca Mountain site cannot meet basic, long-
established public health and environmental protection standards, as it clearly cannot, then
the dump should never be opened. DOE has publicly predicted doses of 200 to 300
mrem/year at 200,000 to 300,000 years after burial of the waste, so now EPA proposes
weakening the standards just enough so that Yucca could still be licensed .
EPA's proposal represents raw politics, is antithetical to science-based public health and
environmental protection, and would doom residents near Yucca to cancer and death at
horribly high rates. All this, just so the nuclear establishment can maintain the illusion of a
solution for the high-level radioactive waste dilemma, so that building new reactors and
keeping the old ones running can be "justified." It must be pointed out that electricity is but
the fleeting byproduct of nuclear reactors. The actual product is forever deadly radioactive
waste. (Comment 0324-7)
23.	The rush to open Yucca despite its fatal scientific flaws is all the more outrageous in
that much of the motivation comes from the effort by the nuclear establishment in industry
and government to maintain the illusion that the high-level radioactive waste dilemma is
not only solvable, but solved. This effort is being pushed largely through pressure to avert
lawsuits against DOE (and thus, American taxpayers) by the nuclear utilities for breach of
contract (DOE failing to begin taking title to irradiated fuel by Jan. 31, 1998), but also
through pressure to build the first new nuclear reactors in the U.S. in over 30 years. The
federal government's attempts to live up to an impossible deadline, and the industry's desire
for a public relations victory on the nuclear waste front, are poor excuses for dooming
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future generations downstream from Yucca to horrendous rates of cancer and cancer death
when the dump leaks massively at some point in the future. EPA should take no part in
such ghoulish games, but should fulfill its congressional mandate to protect public health
and the environment without bowing down to political or economic pressures. (Comments
0324-17 and 0324-32)
24.	The EPA's decision to choose the median rather than the mean is flawed and appears to
be based on the fact that Yucca would not meet a standard based on the mean. (Comment
0341-6)
25.	Another major concern is that EPA's proposal is designed to weaken the standards so
that Yucca Mountain, which is a geologically unsuitable site, can be licensed. (Comment
349-6)
26.	We believe that the revised proposed standard for releases between 10,000 years and a
million years was written to ensure that the Yucca Mountain site will meet the standard. It's
not the first time in the Yucca Mountain nuclear waste repository program that the rules
were made to fit the site, to ensure that it will not be disqualified from consideration.
(Comments 0353-2 and 361-2)
27.1 believe — let me just put it more politely and say these numbers certainly raise a
question as to whether they are coincident by appeal to natural radiation or whether they
are a more transparent attempt to accommodate the industry in what I believe is the worst
site that has been investigated in this country for a nuclear waste repository. (Comment
0368.3-9)
28.1 really question the number that EPA has come up with a 350 millirem median and a
two rem 95 percentile which is indicated by the data from the DOE in that these are the
very numbers that would allow the DOE to license this repository according to the
contractor calculations that have been public for quite a long time. (Comment 0368.3-10)
29.	Unfortunately, EPA's second attempt at drafting a radiation standard .. .is yet another
example of setting regulations to guarantee that the site will be licensed rather than setting
health-based regulations that the site must meet in order to get licensed. (Comment
0368.6-1)
30.	Instead of setting a new and very dangerous precedent for the storage of radioactive
waste throughout the country in order to simply satisfy political pressures to license Yucca
Mountain, the Environmental Protection Agency should fulfill its mission to protect human
health and the environment. We ask you to withdraw the standard immediately and to
propose a standard that is truly protective of public health and the environment for this
generation and generations to come. (Comment 0368.7-4)
31.	Instead these standards appear made to order. By setting a 350 millirem per year
standard for dosages based on a median measure, the EPA is consciously providing a
standard made to fit the limitation of the site. (Comment 0368.9-1)
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32.	In working to set a standard that would enable Yucca Mountain to be licensed, the EPA
has abandoned its real priority. Contrary to EPA's assertion, the proposed standard will not
protect public health for one million years. While the EPA may have set a standard in
place for a million years, that standard is 14 to 23 times weaker than the accepted standard
of protection. In fact, in establishing this new standard, the EPA has relied on questionable
logic and science. ... the uneven application of the concept of uncertainty suggests again
that the EPA is less interested in protecting the public and more focused on licensing Yucca
Mountain and that instead of a consistent logic being applied throughout, the EPA is more
interested in bending the rules to fit their end goal.
(Comment 0368.10-1)
33.	EPA's use of a 350 millirem per year median dose limit is thus a transparent attempt to
keep Yucca licensable despite its clearly unsuitable geology. This median of 350 millirem
per year results in doses of 2,000 millirem per year or two rem per year to the five percent
of people most exposed downstream. EPA's proposal is a shoehorn designed to weaken the
standards so that the geologically unsuitable site can still be licensed rather than requiring
the site to meet public health and environmental protection standards.
(Comment 0368.13-3)
34.	DOE expects Yucca Mountain to release 250 millirem of nuclear radiation every year,
so EPA is lowering its safety standards so DOE can meet them. To simply change these to
weaken public health standards so we can hastily approve Yucca Mountain as a nuclear
waste repository is both dangerous and irresponsible. These standards are designed to
protect the energy and nuclear industries at the expense of public health and safety.
(Comment 0368.14-2)
Response to Issue A:
As set forth in the Energy Policy Act of 1992 (EnPA, Public Law 102-486, 42 U.S.C.
10141 n. (1994)), the role of the Environmental Protection Agency (EPA) regarding Yucca
Mountain is to develop public health and safety standards that are based upon and
consistent with findings and recommendations of the National Academy of Sciences
(NAS). The Agency believes the amendments we are finalizing in this rulemaking are
consistent with the NAS recommendations and are protective of public health and the
environment. The standards were developed based upon our re-examination of the findings
and recommendations of the NAS, consideration of the guidance of the International
Atomic Energy Agency, the Nuclear Energy Agency (NEA) of the Organisation for
Economic Co-operation and Development (OECD), the International Commission on
Radiological Protection (ICRP), and review of international regulatory programs. The final
dose standard of 1 mSv (100 mrem/yr) applicable for the period from 10,000 up to 1
million years is consistent with current national and international recommendations to
protect public health. These recommendations provide a clear basis to conclude that this
standard will also protect public health in the far future.
The standards were not developed based upon the performance assessment in the
Department of Energy's (DOE's) license application for Yucca Mountain. Of course, we
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were aware of publicly available preliminary performance projections such as those in the
final environmental impact statement (FEIS) for the Yucca Mountain disposal system, but
as commenters have pointed out, those preliminary projections could change for use in the
license application; and, as we have now seen in the license application, they did.
However, we did not use either the FEIS or license application projections as a basis for the
standards in any case. We did use a simplified performance assessment code, but it was
not designed to make performance projections of the actual Yucca Mountain disposal
system. Instead, as explained later in Section 6 of this document, we used it to address
comments related to the relative effects of uncertainty on the projections of performance as
time proceeded beyond 10,000 years (this study is in the docket as EPA-HQ-OAR-2005-
0083-0386).
The requirement to set a peak dose standard within the period of geologic stability (on the
order of 1 million years (NAS Report p. 9) is unprecedented in United States regulations.
Therefore, one of the approaches we used was to look to the international community for
guidance on a reasonable approach. Our selected approach for the period between 10,000
years and the time of peak dose out to 1 million years is consistent with most international
recommendations and programs. In general, dose projections for these long periods are
considered to become more qualitative as time goes on because of increasing uncertainty,
i.e., they are looked at as more of an indicator of performance rather than a highly reliable
forecast of performance. Many countries do not impose explicit dose limits for such
periods, but, rather, require only qualitative evaluation of performance. In other cases,
dose limits are specified but are treated as "targets" or "objectives," and strict compliance
with the limit is not required. (Please see Section III.A.2 of the preamble to the final
standards and Section 2 of this document for further discussion of this issue.)
Therefore, all of these considerations, together with international recommendations citing 1
mSv (100 mrem)/yr as a protective public health limit, led us to the chosen dose limit. The
results of the Yucca Mountain Total System Performance Assessment were not a basis for
the standard. In addition, we cannot anticipate whether the Nuclear Regulatory
Commission (NRC) will issue a license even if it is eventually determined that DOE's
performance assessment shows compliance with our standard.
As regards the Superfund criteria (Comment 0113-8), they either do not include or have a
different perspective on factors relevant to Yucca Mountain, for example, the performance
period and intent of the action. Comparing Superfund sites to the Yucca Mountain site is
inappropriate because both the circumstances and the applicable statutory constructs are
vastly different. Superfund addresses current contamination that could expose the public.
EPA developed these standards specifically for the Yucca Mountain site and, by law, they
cannot be applied to Superfund or any other sites.
Comments 0186-13, 0341-6, and 0368.9-1 indicate that the mean of the dose rate
projections should be used rather than the median. We have reconsidered the decision in
the proposed rule to use the median of projected doses and we agree with these comments.
Therefore, we require that the mean of the projections be used for the entire compliance
period. This issue is discussed more fully in Section 7 of this document.
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There are also comments (0209.15-1 and 0368.10-1) that point out the difference in the
proposed dose rate limits before and after 10,000 years and that our use of uncertainty
implies that we are more interested in seeing the Yucca Mountain disposal system licensed
than protecting the public (0301-4 and 0368.10-1). The difference in the pre-10,000 year
and post-10,000 year dose-rate limits has now been reduced since we have responded to
comments and lowered the annual limit after 10,000 years to 1 mSv (100 mrem)/yr - which
has long been recognized internationally as a dose rate limit that is protective of public
health. (Please see Section III.A.2. of the preamble to the final standards for further
discussion) The NAS specifically recommended that EPA's dose rate limit apply at the
time of peak risk (dose); we are implementing this recommendation by considering both
the protection of human health and the environment and the ability of science and
technology to project performance over 1 million years. Therefore, with the irreducible
uncertainties in projections over this unprecedented regulatory period, we believe that a
somewhat higher limit after 10,000 years, 1 mSv (100 mrem)/yr, is both protective and
reasonable. The issue of the two-tiered standard is also discussed in Section 4 of this
document.
In response to Comment 0309-6, 40 CFR Part 191 (the generic standards for spent nuclear
fuel and high-level radioactive waste disposal) did not call for containment of radioactive
waste via geology alone. In 1985, EPA defined "disposal system" as "any combination of
engineered and natural barriers that isolated spent nuclear fuel or radioactive waste after
disposal." This is not only in keeping with the Nuclear Waste Policy Act at 42 U.S.C.
10141(b)(1)(B), it demonstrates EPA's expectations that both manmade and geologic
barriers would play a part in making a successful disposal system. To emphasize that
point, EPA defined "barrier" as "any material or structure that prevents or substantially
delays movement of water or radionuclides toward the accessible environment. For
example, a barrier may be a geologic structure, a canister, a waste form with physical and
chemical characteristics that significantly decrease the mobility of radionuclides, or a
material placed over and around waste, provided that the material or structure substantially
delays movement of water or radionuclides.
Section 1 General Comments
Issue B: Opposed to the standards or the repository in general
1. This facility at Yucca Mountain is built on probable earthquake faults. Radioactive
material should not be stored there in the first place. Money should be spent to solve the
problem at the local site that has nuclear waste as the result of production of electricity or
experimentation. There are 2.5 million people plus potentially sitting in harms way. Every
effort must be taken to protect the residents of Nevada. We are not an uninhabited desert in
which to dump dangerious mateirials. SOLVE THE PROBLEM ANOTHER WAY! I
VOTE!! (Comment 0117-1)
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2.1 stand in solidarity with the people of Nevada in opposition to the Yucca Mountain
Project. It is a desaster for earth and our country. I find the radiation standard is inadequate
and that alone makes the who project unacceptable. Do the right thing for people and the
earth - stop this project now. (Comment 0120-1)
3.1 respectfully request that you revise your standards to truly protect the public health as
regards the yucca mountain project - yucca mountains nevada. i stand united with navadans
and with all caring and compassionate americans in making this request. (Comment 0121-
1)
4.1 am writing to oppose the Yucca Mountain Project. The standard that you envision for
the consequent radiation is unacceptable. I urge you to revise your standards in order to
protect public health. This plan is an injustice to the people of Nevada and any other people
who, in the future, will suffer the results of unsafe burial of radioactive materials.
(Comment 0122-1)
5.	The EPA is committing a terrible injustice to not only Nevadans and the Native
American people of Nevada, but ALL Americans. I stand united with Nevadans in
opposition to the Yucca Mountain Project and the unacceptable radiation standard. I
demand that you once again revise your standard to truly protect the public's health.
(Comment 0124-1)
6.	How can you allow a standard of a high cancer rate in the Yucca Mt. Region where there
is a proposed high level nuclear waste dump planned? Not only is the area unsuitable,
geologically and the land belongs to the Shoshone who don't want the dump, but it will
endanger people along the waste transport routes in the US and increase the threat of
terrorism. No. You would not want cancer. It is an awful thing. Please do not allow it.
(Comments 0127-3 and 0172-1)
7.	We don't want any more radiation. Tighten the waste regulations and stop building
more nuclear plants. (Comment 0138-1)
8.	Whatever it takes, stop so that people including children don't get cancer. (Comment
0152-1)
9.	We urge that the current health and safety standards for radiation exposure be
strengthened not weakened. (Comment 0164-7)
10.	Please rescind your support for standards that would allow high cancer rates in the
populations surrounding Yucca Mountain in the future. (Comment 0166-1)
11.	Please stop the EPA's Carcinogenic Yucca Radiation Rule. (Comment 0168-1)
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12.	For humanity's sake please do not change the Irradiation standards of exposure to
human beings...For whose benefit is this???? Do you want this level Of radiation in your
and your families bodies? Noone will be immune to these generational effects. Listen To
your consciences if such still exists.. (Comment 0171-1)
13.	Withdraw this standard and propose a standard that is protective of public and
environmental health. (Comment 0179-1)
14.	Your cancer-causing Yucca Mountain radiation regulations are outrageous. No one
deserves cancer, especially not children. (Comment 0184-1)
15.	Finally, we urge you to personally attend the hearing so that you can hear and see the
depth of Nevadan's opposition to a weak radiation standard that does not meet the National
Academy of Sciences guidelines, thus needlessly exposing them to public health risks.
Because of the enormity, time span and risk of the proposed project, any standard must err
on the side of caution in order to guarantee the protection of public health and the
environment for hundreds of thousands of years. (Comment 0205-1)
16.	Looking at this document, it says, public health and environmental standard. And what
we're hearing is a radiation standard of 350 millirem. And that's what we're being sold
tonight, and your job, as the Environmental Protection Agency, should be that: To protect
the environment and to listen to the champions of the environment that are here tonight and
not to shove a new standard that's been invented down our throats. (Comment 0209.2-3)
17.	I've been opposed to this issue since Yucca Mountain was talked about. My children
were small at the time, and we had no say in it. It went forward despite many, many, many,
people not wanting it. So I've lost faith and trust in the process and in the people that are
trying to make these changes and push Yucca Mountain through. (Comment 0209.4-3)
18.	The Nevada Department of Justice, in close partnership with the Nevada Agency for
Nuclear Projects, has been at the forefront of Nevada's 20-plus-year struggle to stop
development of the proposed high-level nuclear waste down at Yucca Mountain. And we
will, as the State, be submitting formal extensive comments on this rule. The proposed
Yucca Mountain high-level nuclear waste repository presents great health and safety risks
to Nevadans and is wholly unacceptable to Nevada's leadership. (Comment 0209.6-1)
19.	EPA's revised proposal will advertise it's the most rigorous rule ever because it seeks to
extend health and safety regulations out one million years. Is actually an unprecedented
example of obstination, federal agency collusion, and morally bankrupt standard setting.
(Comment 0209.7-2)
20.	I'm strictly against Yucca Mountain. I live approximately 45 miles away, and I don't
think it's good. I don't like the low-level waste that we have coming through Pahrump,
Nevada, and I think it's dangerous. (Comment 0211.6-2)
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21.	Rather than propose a rule that is in keeping with the recommendations of the NAS,
EPA has on two occasions now, put forward radiation standards which fail to offer
sufficient levels of protection, and that fall far short of the requirement under the law that
they be based upon the work of the National Academy of Sciences. (Comment 0271-1)
22.	Please withdraw the proposed standard and set a responsible limit. Do not plan to leave
a mess which will only cost more to cleanup in the future. (Comment 0274-2)
23.	In reactor communities, the NRC has licensed onsite high-level radioactive waste
facilities and employed the term "temporary" which evidently does not have a definition in
the NRC's dictionary. A4NR does not support the opening of the Yucca storage site with
its suspicious science (ex. Geology), and its inadequately tested barriers. (Comment 0294-
1)
24.	EPA's proposed standard is inconsistent with the recommendations of the National
Academy of Sciences (as required by the Energy Policy Act of 1993) and the July 9, 2004
ruling of the U.S. Circuit Court of Appeals for the District of Columbia. The proposed rule
violates and contradicts EPA's historical approach to public health and environmental
protection in which standards were progressively toughened. In addition, the proposal sets
a disturbing and dangerous precedent for future regulation of radiological and hazardous
materials. (Comment 0309-1)
25.1 conclude that EPA has no alternative but to withdraw the proposed rule and reissue a
new draft standard that abandons the arbitrary and scientifically unjustified radiation
exposure limits; that continues strict groundwater protection requirements through the
period of maximum exposure; that eliminates statistical gerrymandering through the use of
median vs. mean calculations; that removes inappropriate and illegal intrusions into the
NRC regulatory arena; and that returns to EPA's historical approach to radiation and
environmental protection. (Comment 0309-2)
26.	Please! No! Do not weaken the radiation regulations for Yucca Mts. People before
greed. (Comment 0332-1)
27.	Yucca Mtn. is an integral part of the U.S.A. - Do we desecrate even any spot of our
land we now hold dear? (Comment 0333-1)
28.1 object to the new radiation standard for Yucca Mountain. Please don't endanger our
lives. (Comment 0335-1)
29.1 object to the new standards fro the Yucca Mountain. It will endanger many lives.
(Comment 0337-1)
30.1 strongly object to the weakening of the radiation regulation for Yucca Mountain.
(Comment 0339-1)
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31. Those who are elected to make decisions for the good of our people and country need
to consider better radiation standards for the Yucca Mountains. It will endanger many lives.
(Comment 0343-1)
32.1 object to the new radiation standard for Yucca Mountain. It will endanger many lives.
(Comment 0344-1)
33.1 object to the new radiation standards for Yucca Mountain. It will endanger many
lives. (Comment 0347-1)
34.1 do not think that Yucca Mountain is a safe storage facility for nuclear waste. Nor do I
think the methods of transportation are safe enough get the waste there. (Comment 0366-1)
35. We find this proposal, ... to be totally unacceptable to protect public health and safety.
And that is indeed EPA's mission or so we wish to believe. ... I should hope that EPA in
its reconsideration of this unacceptable rule will be begin to take into account the problems
of the future. (Comment 0368.4-2)
36.1 strongly OPPOSE the EPA's revised radiation protection standard for Yucca
Mountain. This proposal does not come close to protecting public health and does meet
comply with federal law. (Comment 0371-1)
Response to Issue B:
The commenters generally object to EPA's proposed standards, the dose rate levels they
see as insufficiently protective, or the Yucca Mountain project. As discussed in greater
detail in the preamble to the final rule, and in Section 2 of this document, EPA has, after
considering a variety of factors including public comment on the proposed rule, established
the public health and safety standard at Yucca Mountain applicable after 10,000 years as 1
mSv (100 mrem)/yr. This post-10,000-year standard protects the public health and safety
and is appropriate given all the relevant factors considered by the Agency when projecting
exposures very far into the future. In addition, by applying over the entire period of
geologic stability beyond 10,000 years (up to 1 million years), it will capture the peak dose
during that period. By doing so, our final rule is consistent with the NAS recommendation
to have a standard with compliance measured "at the time of peak risk, whenever it occurs
within the limits imposed by the long-term stability of the geologic environment, which is
on the order of one million years." (NAS Report p. 2) See the discussion of geologic
stability in Section 10 of this document.
Relative to the comments regarding transportation, the Agency has not issued standards for
the transportation of the waste to Yucca Mountain since it was not given the authority
under the Energy Policy Act of 1992 to do so. It is the responsibility of the Department of
Transportation and the Nuclear Regulatory Commission to regulate that transportation.
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Section 1 General Comments
Issue C: Use of the standards as a precedent for other sites
1.	There is a big reason not to set a standard of 350 mrem per yr. It will be used as a
precedent for other regulations. My State of Wisconsin is high on the "hit list" for a second
repository in granite in the Wolf River baolith and then, will we need a 3rd repository or
what? Are you thinking of the future use of your standard?? This is not a site-specific
standard for Yucca Mt. when you use allowable "natural" doses elsewhere in the U.S. for
your measurements. (Comment 0113-9)
2.	We are on the brink of final decisionmaking now. And your decision will be used by the
rest of the world as a reference for their repositories. (Comment 0113-11)
3.	These proposed regulations allowing 350 millirem per year radiation doses are
completely unacceptable and must not be allowed to set a precedent to be applied at other
radioactively contaminated sites across the country because they represent a large-scale
weakening of environmental and public health protection standards. (Comments 0126-2,
0127-2, 0130-3, 0133-5, 0135-5, 0137-5, 0144-4, 0146-5, 0147-5, 0148-5, 0150-4, 0159-5,
0163-5, 0164-4, 0175-4, 0177-4, 0182-3, 0189-3, 0190-4, 0302-20, 0310-4, and 0324-2)
4.	This proposed rule may establish a dangerous precedent as it is inconsistent with
internationally accepted radiation protection standards and could seriously impact locations
around the country with radioactive contamination. (Comments 0132-3, 0149-1, and 0195-
3)
5.	The new EPA standard for the second period, 10,000 to one million years, is worse, as it
could set a new precedent for the world. No other organization has suggested setting any
environmental protection standard beyond 10,000 years. We simply have no historical
record upon which to base this kind of policy, no international body of radiation protection
scientists nor nuclear engineers participated in the establishment of this precedent-setting
standard. This precedent should not be set without major international participation, careful
science policy studies and much discussion. (Comment 0209.9-4)
6.	This proposed standard will set a terrible precedent because it is contrary to
internationally-effected radiation protection standards and lowers the bar on radiation
protection at other contaminated sites across the country. I find little comfort in the fact that
you're not just putting Nevadans in harm's way. (Comment 0209.13-4)
7.	The EPA proposed standard is not only unacceptable for Yucca Mountain, but also
unacceptable for any other potential geologic repository site. The EPA proposed rule would
likely set a dangerous precedent that would apply to any other site or sites that might be
considered if Yucca Mountain is found unacceptable. In the event that Yucca Mountain
should be licensed and constructed under the EPA proposed rule, a dangerous and
unacceptable precedent would apply to any other sites that might be considered for a
second or subsequent repository. We believe that the 15 millirem per year maximum
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exposure threshold, coupled with the 4 millirem groundwater protection standard, would
provide a safe and equitable standard for Yucca Mountain and for any other site or sites
which might be considered for repository development. As residents of Wisconsin, we are
concerned that the EPA proposed rule might set a precedent for future licensing of
repository candidate sites in granite. DOE seriously studied potential candidate sites in
Eastern and Midwestern granite formations, including many formations in Wisconsin,
between 1976 and 1986. EPA must assess the potential implications of the proposed rule
for other geologic repository sites before taking any final action in this docket. (Comment
0275-3)
8.	If approved, the new EPA standards for Yucca, which drastically relax current regulatory
standards for radiation protection, would have consequences far beyond the Yucca
Mountain Repository. The proposed rule would also set a dangerous precedent for
relaxation of all radiation protection standards at DOE sites everywhere. (Comment 0301-
10)
9.	The EPA proposed standard is not only unacceptable for Yucca Mountain, but also
unacceptable for any other potential geologic repository site. The EPA proposed rule would
likely set a dangerous precedent that would apply to any other site or sites that might be
considered if Yucca Mountain is found unacceptable. In the event that Yucca Mountain
should be licensed and constructed under the EPA proposed rule, a dangerous and
unacceptable precedent would apply to any other sites that might be considered for a
second or subsequent repository. There are several credible scenarios under which DOE
might consider other repository sites in addition to Yucca Mountain, or in place of Yucca
Mountain... As residents of Wisconsin, we are concerned that the EPA proposed rule might
set a precedent for future licensing of repository candidate sites in granite.. EPA must
assess the potential implications of the proposed rule for other geologic repository sites
before taking any final action in this docket. (Comments 0303-2. 0325-2, and 0325-3)
10.	EPA's proposal would set a very dangerous precedent that could be applied across the
U.S., not just at Yucca Mountain. EPA has for decades declared any radiation dose above
15 to 25 mrem/yr to be "non-protective of public health." Its general policy has been to
regulate exposures to limit cancer rates to 1 in. 10,000 persons exposed, or even to 1 in 1
million persons exposed. For example, EPA limits radioactivity in drinking water to 4
mrem/yr, air emissions at 10 mrem/yr, and Superfund cleanups to the equivalent of roughly
0.03 to 3 mrem/yr. EPA has gone on record, again and again, that radiation doses of 100
mrem/yr produce unacceptable levels of risk, But EPA's 350 mrem/yr proposed standard
for Yucca would be a 23-fold increase in "allowable" radiation over the 15 mrem/yr
standard, and would more than triple the amount of radiation exposure EPA has repeatedly
stated produces unacceptable levels of risk . If EPA gets away with this, it could set a
precedent to rollback cleanup efforts at other radioactively contaminated sites across the
country, including other radioactive waste dumps, nuclear power plant sites, and nuclear
fuel chain facilities. There is the added danger that EPA could attempt to apply such inter-
generational double standards to other polluted sites suffering nonradioactive, toxic and
hazardous material contamination, allowing for much higher cancer rates (and other disease
rates) to future generations. (Comments 0324-6, 0324-12, and 0324-21)
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11.	Warning! Please don't put future generations at risk for lowering the bar on radiation
protection for all nuclear sites. Please. (Comment 338-1)
12.	The new radiation standards for Yucca Mountain lower the bar for radiation protection
for all nuclear sites in the United States. (Comments 0318-1, 0319-1, 0320-1, 0321-1,
0323-1, and 0343-2)
13.	The new radiation standard for Yucca Mountain lowers the bar on radiation protection
for all nuclear sites in the U.S. The EPA is endangering future generations. (Comment
0345-1)
14.	Allowing a 350 millirem per year radiation dose has the potential to set a precedent to
be applied at other radioactively contaminated sites across the country, including standards
for cleanup efforts and other radioactive waste dumps, nuclear power plant sites and
nuclear fuel chain facilities. (Comment 0349-2)
15.	The proposed standard is contrary to internationally accepted radiation protection
standards and lowers the bar on radiation protection at other contaminated Department of
Energy (DOE) sites around the country, including those in New Mexico. (Comment 0354-
4)
16.	These proposed regulations allowing 350 millirem per year radiation doses are
completely unacceptable and must not be allowed to set a precedent to be applied at other
radioactively contaminated sites across the country because they represent a large-scale
weakening of environmental and public health protection standards-the worst such
standards, by far, in the Western world-in violation of international norms. This inter-
generational immorality must also not be applied to other EPA jurisdictions, such as non-
radioactive, toxic and hazardous chemical contaminated sites. (Comment 0355-3)
17.	EPA has said that doses of over 100 millirems/year produce "unacceptable risk" so a
dose of 350 is unacceptable to the public. (Comment 0367.2-13)
18.	They must not be allowed to set a precedent because they represent a large-scale
weakening of the environmental and public health protection standards. (Comment 0368.1-
2)
19.	We also do believe that these standards unfortunately, if they go forward, would set a
dangerous precedent. And now suddenly I should hope that EPA in its reconsideration of
this unacceptable rule will be begin to take into account the problems of the future.
(Comment 0368.2-5)
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20.	By throwing away decades of precedent, the EPA is setting a new and very dangerous
precedent for the storage of radioactive waste throughout the country, if not overseas as
well. ANA is concerned about the potential of this precedent for other DOE cleanup sites,
but it could also roll back cleanup efforts at other radioactively contaminated sites across
the country, including nuclear power plant sites, other radioactive waste dumps, and other
nuclear facilities. (Comments 0368.9-3 and 0368.12-2)
21.	EPA's proposal would set a very dangerous precedent that could be applied across the
U.S., not just at Yucca Mountain. EPA has for decades declared any radiation dose above
15 to 25 millirem per year to be nonprotective. Its general policy has been to regulate
exposures, to limit cancer rates to one in 10,000 persons exposed or even to one in one
million persons exposed. There is the added danger that this precedent could be applied to
other polluted sites suffering from nonradioactive but toxic and hazardous chemical
contamination allowing for much higher cancer rates and other disease rates to future
generations. (Comment 0368.13-2)
Response to Issue C:
The Energy Policy Act of 1992 (EnPA, Public Law 102-486, 42 U.S.C. 10141 n. (1994))
gave authority to EPA to set site-specific standards applicable only to Yucca Mountain.
The EnPA also prescribed that EPA's standards must be "based upon and consistent" with
recommendations of the National Academy of Sciences (NAS). The NAS specifically
recommended that the site-specific standards applicable to the Yucca Mountain repository
apply at the time of peak dose within the period of geologic stability (which the NAS
defined in the context of Yucca Mountain to extend to as long as about 1 million years). It
is unreasonable to compare this action to standards developed in other regulatory contexts
that apply for much shorter periods. Like the portion of the standard that applies for 10,000
years, traditional EPA rulemakings and Superfund cleanups continue to rely upon the risk
range and limit incremental risk. The Agency recognizes the uniqueness of a peak dose
standard within the period of geologic stability of the Yucca Mountain region in United
States regulations and the need for a higher dose limit to maintain the same level of
certainty as for shorter times. No other United States waste disposal program, either
radioactive or non-radioactive, intends to extend its compliance period to 1 million years.
In response to Comments 0113-9, 0126-2, 0127-2, 0130-3, 0133-5, 0135-5, 0137-5, 0144-
4, 0146-5, 0147-5, 0148-5, 0150-4, 0159-5, 0163-5, 0164-4, 0175-4, 0177-4, 0182-3, 0189-
3, 0190-4, 0302-20, 0310-4, 0324-2, 0324-12, 0324-21, 0349-2, 0355-3, and 0367.2-13 in
which commenters stated that a 3.5 mSv (350 mrem)/yr standard is unacceptable, we have
reconsidered our position for this action. As a result, we have established 1 mSv (100
mrem)/yr as the dose rate limit after 10,000 years. This is discussed further in Section 2,
Issue D.
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In response to Comments 0113-11, 0132-3, 0149-1, 0195-3, 0209.9-4, 0209.13-4, 0275-3,
0301-10, 0303-2, 0324-6, 0324-12, 0324-21, 0325-2, 0325-3, 0338-1, 0354-4, 0355-3,
0349-2, 0345-1, 0368.1-2, 0368.2-5, 0368.9-3, and 0368.12-2: Just as we have consulted
international sources, we recognize that actions taken by the United States will likely be
referenced internationally, but that does not mean they will be adopted elsewhere. In fact,
in establishing a compliance period of 1 million years, we have responded to the decision
of the U.S. Court of Appeals for the D.C. Circuit and have established a standard applying
at peak dose. The international sources that we have consulted have provided a basis for
identifying a standard for the far future that is protective of pubic health and safety.
Similarly, in the end, other countries and agencies will establish standards based upon their
individual situations, not based upon the actions of EPA.
Therefore, while we conclude that our standards will protect public health to the time of
peak dose within 1 million years, there is no basis for assuming that this same standard will
necessarily be applied to any other waste site in the United States or internationally.
Section 1 General Comments
Issue D: Generally supports the proposed amendments
1.1 would like to thank the EPA for having the political courage to (finally) propose
reasonable radiation standards for the Yucca Mtn. project. Even with the amended
standards, Yucca Mtn. is being held to the most stringent environmental standards ever
imposed on any industry or project, let alone on any other energy source. (Comment 0201-
1)
2.	We believe that there are fundamental flaws in the approach that forms the basis of the
proposed rule. However, we realize that there are practical considerations that require that
the proposed rule should be adopted in essentially its current form. (Comment 0215-1)
3.	NARUC supports this latest EPA revision as both reasonable and justifiable. We
generally agree with most elements of the proposed revision, including the specified
compliance period and dose limits. (Comment 0217-la)
4.	The proposed standards for the Yucca Mountain Project are fully supported by myself.
	The hydrology and geology of the site is well characterized and the models are both
sound and conservative. The 10,000 year standard (15 mrem) for such a human endeavor
is both conservative and practical. .. .The 1,000,000 year standard (350 mrem) is both
sound and conservative. These standards are based on sound science and conservative
modeling beyond which we venture into incredible and impractical territories. - (Comment
0220-1, 0212-1)
5.	If it is not feasible to safely predict the behavior of the planet over that period of time, let
alone a huge tightly packed body of the deadliest toxins known to man, let us acknowledge
that to each other, and proceed responsibly (Comment 0306-2).
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6.	With respect to the specific questions posed by EPA on elements of the proposed
standard (e.g., median vs. mean; treatment of features, events, and processes; Reasonably
Maximally Exposed Individual) Duke endorses the comments provided by NEI on the
behalf of the nuclear industry. (Comment 340-4)
7.	The SRS CAB has analyzed the issues and concluded that the public health standards
proposed by the EPA for Yucca Mountain are fair, adequate, and consistent with the
standards prescribed for similar endeavors. Simply put, the proposed EPA standards are
fair, technically adequate, and responsive to the legitimate needs of the citizens of both
Nevada and the other 49 states in our country. (Comment 0368.11-1)
Response to Issue D:
The standards we have established are protective of public health and the environment,
responsive to the DC Circuit ruling, and provide clear and adequate measures for DOE to
follow and NRC to implement. Based upon public comments and further deliberations, the
Agency has determined that the compliance measure will not be the proposed median, but
rather the arithmetic mean in the post-10,000-year standard and the post-10,000- year dose
rate limit is 1 mSv (100 mrem)/yr. The reasons for that are discussed in more detail in the
preamble to the final standards and Section 2 of this document.
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Section 2 Dose Limits
Issue A: Definition of Reasonably Maximally Exposed Individual
1. The EPA calculated this proposed standard using what is known as a Reasonably
Maximally Exposed Individual (RMEI). RMEI is defined as a "standard man." The EPA is
willingly ignoring the potential impacts to children, women, mothers, the elderly, and
others who may in fact be more vulnerable to radiation exposure. (Comments 0131-1 and
0195-7)
2.1 am aware of the "standard man" calculation which totally ignores the existence of
children, women, mothers, and the elderly and the radiation's potential impacts on their
well being. Children are not "negligible"! (Comments 0130-6, 0132-2, and 0140-3)
3.	Your agency has willingly ignored the potential effects that this project may have on
children, women, and the Native American people of Nevada. This is an unjust and
irresponsible policy. (Comment 0354-3)
4.	... EPA has written the regulations for Yucca Mountain in such a way that the biosphere
and human behaviors essentially are fixed by rule and are assumed not to change much at
future times. This is a reasonable approach, in my view, because by fixing the biosphere
and human behaviors by rule, performance assessments and compliance demonstrations
can focus on the capabilities of natural and engineered barriers in limiting releases to the
accessible environment, which is the important concern in disposal of long-lived
radioactive wastes, and largely meaningless speculation about how exposure pathways and
doses might change at far future times is removed from consideration. (Comment 0186-16)
5.	We're going to treat everybody the same over a period of time. And I think those
receptors are individuals differ, and their exposure to hazards — the lifestyle, what they eat,
the rabbits and trees. They're not just numbers, those are part of who we are, the land that
fits our identity and how we construct threats and risks and hazards in our community.
(Comment 0209.5-3)
6.	During this (10,000 years) time period, the concept of protecting a Reasonably
Maximally Exposed Individual (RMEI) has some validity. Real people live in locations
near the facility... The nature of a potentially exposed individual 100,000 years in the
future is somewhat different. These are hypothetical people. ... should be treated
probabilistically with regards to their lifestyle, consumption of food, and consumption of
water as it affects radiation exposure. They should also be treated probabilistically with
regards to location within the affected region. For these hypothetical people the protection
of a maximally exposed individual is an overly conservative regulatory approach.
(Comment 0215-4)
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7.	We believe that the RMEI approach is not an appropriate basis for .... regulatory limits
... and that the proposed limits are inappropriately conservative. However, we are not
proposing a change to the proposed rule. We do see value, however, in the interpretation of
the RMEI criterion as a conservative bound to the achievement of a probabilistic safety
goal. The prescriptive guidelines provided by EPA for the analysis of RMEI should be
adopted as they are presented. (Comment 0215-6)
8.	Under the Individual Protection Standard the term "reasonably maximally exposed
individual" is used, which is too ambiguous; later, loosely defined as having "... a diet and
living style representative of the people who now reside in the town of Amargosa Valley,
NV." This is a disturbing departure of the usual practice of the "subsistence farmer"
scenario to assess maximum exposure. To be sure, such a lifestyle does actually exist in
Amargosa Valley. The point is to define a "critical group", which according to the
International Commission on Radiological Protection explicitly states that a critical group
"represents an extreme" of radiation exposure "to insure that no individual doses are
unacceptably high."(ICRP Publication No. 46, 1985, p.9) This reasoning is in the best
interest of the public health of future generations unlike the definition in the current
proposed rule. (Comment 0268-6)
9.	The NAS directed the use of the average member of the critical group for the receptor.
The EPA used the reasonably maximally exposed individual (RMEI). The pre-10,000 years
RMEI lives in Amargosa Valley. Will EPA justify using the same RMEI post-10,000 years
when released contamination will start at the mountain and extend all the way to Death
Valley? Could some other individual at another location be the maximally exposed
individual for the new time period? DOE should have to determine and justify the
parameters defining the new RMEI and use this possibly time varying definition post
10,000 years. (Comment 0273-1)
10.	We agree with EPA's decision to maintain its choice of the RMEI as presently defined
and not attempt to redefine any characteristics of the RMEI for the beyond 10,000 year
analysis. As EPA correctly observes, the present day RMEI is a conservative
approximation of how future individuals will live. The present-day RMEI lives a rural-
residential lifestyle in a very dry climate, hence, heavily uses groundwater. Such an
individual would be more vulnerable to groundwater contamination than would be an
individual living under wetter climate conditions where rainfall and surface water would be
more plentiful. A constant and conservative definition of the RMEI is a prudent and
appropriate choice for any long-term repository safety analysis. (Comment 0298-19)
11.	Both agencies use of the "standard man" as their model "dose receptor" ignores the
higher vulnerability to radiation of fetuses, children, women, subsistence farmers, the
elderly, those with weakened immune systems, and Native Americans living a traditional
lifestyle. These populations must be fully protected against radiation leaking into the
environment. (Comment 0310-3)
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12.	Re: EPA's comment on page 49019, column 3, that "The standard described above
applies, for a period of 10,000 years after disposal, and is to be measured against exposures
to the RMEI at a location outside the controlled area (in the "accessible environment")."
How does the federal government propose to control the "controlled area" for 10,000 years,
or for a million years? Will institutional controls last that long?
What is to prevent humans from moving into the "controlled area" and growing crops or
livestock, and drilling wells into the severely contaminated groundwater table for drinking
and irrigation water? (Comment 0324-19)
13.	Under the Individual Protection Standard the term "reasonably maximally exposed
individual" is used, which is too ambiguous; later, loosely defined as having "... a diet and
living style representative of the people who now reside in the town of Amargosa Valley,
NV." This is a disturbing departure of the usual practice of the "subsistence farmer"
scenario to assess maximum exposure. To be sure, such a lifestyle does actually exist in
Amargosa Valley. The point is to define a "critical group", which according to the
International Commission on Radiological Protection explicitly states that a critical group
"represents an extreme" of radiation exposure "to insure that no individual doses are
unacceptably high."(ICRP Publication No. 46, 1985, p .9) This reasoning is in the best
interest of the public health of future generations unlike the definition in the current
proposed rule. (Comment 0328-5)
Response to Issue A:
As EPA stated in the preamble to the proposed amendments, the RMEI is not a subject of
the current rulemaking: "Comments on the definition of the controlled area and
specification of the RMEI are outside the scope of today's proposal. We will not consider
or respond to comments on these topics." (70 FR 49023) For further discussion of this
subject, please see the 2001 Response to Comments document. (Docket No. EPA-HQ-
OAR-2005-0083-0043)
Section 2 Dose Limits
Issue B: Support the use of 350 mrem CEDE/vear after 10,000 years
1. The proposed standards for Yucca Mountain are more than adequate. 1. They apply to a
hypothetical human living less than 15 miles from the site, where no one lives now. 2. They
enforce a level of risk no greater than what millions of American live with every day
because of natural radiation. 3. Americans, including Nevadans, have enjoyed the benefits
of nuclear energy for decades. It's time to accept this minimal risk as the cost for reduced
greenhouse gases, better homeland security, and less reliance on foreign oil and natural gas.
We, as a nation, chose and accepted the risk of nuclear energy in exchange for its benefits.
It's our responsibility to now minimize that risk by placing its byproducts in a safe, secure
place rather than stacked up in temporary locations near large populations and water
sources. (Comment 0089-1)
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2.	We are concerned by news articles we have read, where some people have characterized
this new post- 10,000-years standard as too lax, when in fact it sets the most protective
long-term safety requirements ever established by EPA. Therefore, in the attached report
we review EPA's current regulations for managing the long-term risks of other radioactive
and non-radioactive materials. This review confirms that there are no cases where EPA
regulates any type of risk past 10,000 years. The review also shows that the actual long-
term risks from many activities that EPA could regulate are indeed significant. Therefore
the proposed Yucca Mountain standard is not consistent with EPA's management of risks
from its other hazardous non-radioactive and radioactive materials, but instead is more
protective. (Comment 0174-1)
3.	Support use of a dose limit until the time of peak dose, but it does not need to be the
same as for the shorter compliance period. (Comments 0180-4; 0181-4)
4.	The EPA has succeeded in creating a standard that allows a reasonable person to decide
if a repository at Yucca Mountain is a good thing or a bad thing. The proposed rule avoids
pretending we can determine a repository would impose radiation exposures equivalent to a
few chest X-rays per year to local people in - take your pick - 200,000, 500,000, or
1,000,000 years. (Comment 0185-1)
5.1 believe it is reasonable that the dose criterion (or criteria) used to define acceptable
performance in the time period beyond 10,000 years can be less stringent than the dose
criterion that applies over the first 10,000 years. (Comment 0186-1)
6.	If the EPA is proposing to require Yucca Mountain to safely contain radiation, including
through events such as earthquakes, volcanic activity, and heavy water events, at levels of
no increased radiation to the environment beyond natural background levels for the next
10,000 years, and then for the next million years at levels not above the current amounts of
environmental radiation, then I would very much support such standards. (Comment 0191-
1)
7.	It would be short sighted and even dangerous to demand radiation standards so
extremely tight that they affectively ban beneficial uses of nuclear energy. Alternatives to
nuclear energy also have risks to public health, such as oil spills/fires, coal mine collapses,
acid rain, C02 exhaust, global warming, etc. Should be also ban life saving medical
diagnostics and radiation cancer treatments because we have no place to safely store the
medical waste with small amounts of radiation? (Comment 0193-3)
8.	It is absurd to claim that EPA's proposed standards do not sufficiently protect the public.
Public health risks that are literally millions of times higher are routinely and readily
accepted all the time. (Comment 0201-3)
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9. The claim of insufficient public health protection is also absurd given that, despite
decades of thorough study, no correlation between dose rates (within the range of natural
background) and cancer incidence has ever been detected. Even if one were to accept the
linear-no-threshold (LNT) theory of cancer risk from radiation exposure, dose rate limits
that are a tiny fraction of natural background are impossible to defend, due to their clear
inconsistency. Such limits are, by definition, selectively applied. How can such small dose
rates be declared unacceptable, but ONLY if their source has something to do with the
nuclear power industry!! Meanwhile, natural exposures, or exposures from flying or
medical exposures are perfectly fine. (Comment 0201-4)
10.1 would also like to point out that it is scientifically invalid to employ the LNT theory
(allowing exposures to be controlled at levels orders of magnitude under those for which
any health effects are actually seen) but then establishing exposure limits in terms of dose,
as opposed to person-dose. LNT clearly states that the overall health effects are directly
proportional to person-dose. Individual "risk burden" is simply not a meaningful concept.
If EPA wishes to use LNT, it should create pollutant release limits, based upon calculations
of resulting collective exposure, as opposed to establishing individual exposure limits.
(Comment 0201-5)
11.	Individual exposure limits are only scientifically valid if the concept of a threshold is
being invoked (which would justify a limit at or near the threshold). Of course, if a
threshold for radiation exposure was accepted as the scientific basis, all of this would not
even be an issue, as dose rates under 1000 mrem per year would not be regulated at all
(since there is no evidence at all of health effects from annual exposures under 1000
mrem). Basically, Yucca Mtn. dose rate limits that are a tiny fraction of background (i.e.,
15 mrem) are impossible to defend either way, i.e., whether or not LNT theory is accepted.
(Comment 0201-6)
12.	EPA needs to stick to its guns on the proposed Yucca Mtn. dose standards. Returning to
the old standards would be completely inconsistent (w/ all other regulations), scientifically
and logically indefensible, and very bad public policy. (Comment 0201-7)
13.	The early-time standard will waste Americans', meaning consumers' and taxpayers',
money because it is simply too low. The proposed EPA standard for Yucca Mountain will
keep potential exposures far below any level that has ever been shown to cause any human
health effects. This after thousands of studies of hundreds of thousands of exposed
individuals as well as controls over the past 20, 50, and even 100 years. The official
position of the Health Physics Society states in part: Below 10 rem, risks of health effects
are either too small to be observed or are nonexistent. That was not 10 millirem, that was
10,000 millirem. If we can't see the effects on people of 10,000 millirem, on real people,
why are we falsely attempting to protect Nevadans to 15 millirem per year? (Comment
0209.9-1)
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14.1 am a proponent of your standard. I think it will work. In terms of danger, as with
commercial nuclear facilities, the individuals working at the station or at the mountain
experience the highest dangers. The public, basically, experience no danger at all.
(Comment 0211.7-2)
15.	This comment pertains to the EPA's "proposed annual peak dose limit of 350 mrem
applicable beyond 10,000 years." In brief, I believe it is an acceptable standard, although
other similar standards would also be acceptable. Nonetheless, it would be unacceptable to
create the potential for a major human disaster (i.e., "catastrophic consequences," in EPA's
words) no matter how far into the future we are considering. In short, we must not
"booby-trap" the Earth. As reflected in the EPA's stated rationale, meeting the proposed
RMEI standard of 350 mrem/yr for Yucca Mountain would satisfy this demand, because
the total doses are limited to levels that are now experienced by many people from natural
radiation with no observed ill-effects. For these reasons, the EPA's proposal seems to me
to be reasonable in its overall thrust and its numerical parameters. (Comment 0313-1)
16.	Accordingly, we recommend that these proposed standards be approved and a final
DOE rule be expeditiously established to guide subsequent DOE actions to license,
construct, and operate the Repository. (Comment 0329-1)
17.	Commenting specifically on the proposed annual dose limit, Duke agrees with EPA that
the 15 mrem annual dose limit (currently applied for the first 10,000 years) should not be
applied to the entire time frame of the proposed million year regulation. It would be
inappropriate to impose such an extremely restrictive exposure limit on hypothetical far
future populations. (Comment 340-5)
18.	We, Coalition 21, a volunteer organization of about 50 members in southeastern Idaho,
support the EPA radiation release standards for the planned Yucca Mountain disposal site,
as extended beyond 10,000 years. The requirement that no one should receive more than
350 mr in addition to the present local background of about the same amount is certainly
protective of human health. As the EPA points out, many Colorado residents receive this
total amont of 700 mr per year already, without ill effects. Thus, even the 15 mr standard
up to 10,000 is excessive. (Comment 350-1)
19.	The proposed revisions to the EPA rule appropriately blend policy considerations and
technical approaches in a manner that will enable evaluation of repository performance in
comparison to a peak dose regulatory standard. Setting the level of protection is a policy
decision, and EPA's recommended value of 350 mrem/yr (an annual risk level of
approximately 2 x 10"4) is not inconsistent with other routine risks that society accepts
today. (Comment 0352-18)
20.	It should be noted that the peak dose limit proposed by EPA is well below the doses in
the range of several rem (thousands of millirem) that EPA and an earlier committee of the
NAS calculated could be produced by consumption of groundwater near a repository. As
EPA pointed out at the time of promulgation of the original standard for geologic
repositories: "This possibility is inherent in collecting a very large amount of radioactivity
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in a small area." These calculations were made at the time that the original standards for
geologic repositories were under development, and the possibility of such doses was not
viewed at the time as a reason for rejecting the concept of geologic disposal. A dose
standard orders of magnitude lower than levels understood to be an inherent possibility of
geologic repositories could well have the indirect effect of forcing a change in national
policy concerning the acceptability of geologic disposal. Any such decision is appropriately
one to be made by Congress and the President, not as the inadvertent result of a regulation
developed pursuant to a law that was clearly intended to expedite the development of a
repository. (Comment 0352-26)
21.	We agree with the dose limit for the period after 10,000 years being set at a higher level
since there is greater uncertainty in forecasting so far into the distant future. Selecting 350
millirems per year for that period for the reasonably maximally exposed individual is well
reasoned and drawing that comparison to levels people in other Western States are
routinely exposed to makes good sense. And we feel the public can relate to that better
than trying to understand what a millirem is. (Comment 0368.5-2)
22.	Let me conclude by saying that we believe the proposed revised rule meets the
objectives laid out in the discussion accompanying the revision and that it is responsive to
the court ruling, protective of public health, reflective of best science and cognizant of
limits of long-term projections, implementable by NRC in its licensing process, and limited
in scope and focused on aspects critical to the above goals. (Comment 0368.5-5)
Response to Issue B:
After considering public comments, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) as the individual-protection standard to apply for the period between 10,000
years and 1 million years. Instead, we are establishing 1 mSv/yr (100 mrem/yr) as the
individual-protection standard applicable beyond 10,000 years. This level is widely
accepted and recommended, both internationally and domestically, as a protective overall
public dose limit for practices involving the use of radioactive material. We will, however,
address the comments that indicated support for the proposed dose standard because much
of their reasoning can also be applied to the 100 mrem/yr final dose standard, although we
cannot state that the commenters would also support the stricter standard.
Commenters offered a variety of reasons for supporting the proposed limit of 350
mrem/year beyond 10,000 years. While Commenters 0191, 0313, 350, 0368.5 agreed that
the use of background radiation is an appropriate point of reference at very long times (and
to address uncertainties in projections at such times), others cited the potential
consequences of setting standards that would hold the repository to unrealistically stringent
performance requirements. Still others pointed to risks to individuals (as opposed to
populations) from radiation at such levels as justification for a higher dose limit (although
our 15 mrem/yr standard for the first 10,000 years was also criticized on this score).
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Commenter 0193 cited the potential consequences to the country in terms of future use of
nuclear energy, or increased use of fossil fuels, if the Yucca Mountain disposal system
cannot be licensed, while Commenter 0089 also refers to the responsibility to manage
waste generated from the historic use of nuclear power. These considerations are not a
factor in the standards we have issued, although we have received numerous comments
suggesting otherwise (see Section 22 of this document). Although the national policy is to
pursue geologic disposal of spent fuel and high-level waste, our role in implementing that
policy is limited to establishing standards to ensure the disposal system will adequately
protect public health and safety and the environment.
Commenters 0201 and 0209.9 argue that the proposed dose limit of 350 mrem/yr is
insignificant in terms of its demonstrated health impacts. These commenters point to
studies and such organizations as the Health Physics Society to support their position that
individual dose limits are not meaningful at such low levels (and may be
counterproductive). Commenter 0201 further states that the appropriate measure of impact,
if one assumes a linear dose-response relationship, would be person-dose, as radiation
health effects can be estimated only with respect to populations, not individuals.
Commenter 0201 suggests that an appropriate way to incorporate considerations of
population exposures would be to formulate a standard in terms of cumulative releases over
time of individual radionuclides, correlated to health effects, as we did in 40 CFR part 191.
However, NAS did not recommend a release-limit approach, noting that "this form of the
standard does not provide any information about how these releases affect public
health.. .and so is incomplete unless coupled with a calculation of individual (or
population) risk (or dose or health effects)." As a result, even if such calculations are
provided, "such a requirement would [not] provide additional protection over that provided
by the individual-risk limit." (NAS Report pp. 63 and 120, respectively) We also
concluded that the conditions at Yucca Mountain did not lend themselves to exposures of
wider populations than those in the direct pathway of potential contamination, e.g., through
surface water or more widely connected ground-water systems, which was a primary
consideration in formulating the generally applicable standards in 40 CFR part 191. We
also note that NAS recommended a standard to limit exposures to individuals, and
concluded that such a standard would also effectively protect populations. In fact, on page
120 of the NAS Report, there is this statement: "We conclude that there is no technical
basis for establishing a collective population-risk standard that would limit risk to the
nearby population of the proposed Yucca Mountain repository."
We agree with the comments in the sense that risk as an indication of health detriment, as
recommended by NAS, is less useful over the time frames addressed by our regulation, and
may be misleading. Estimates of risk for individuals, correlated to dose or intake, are
available from various sources, including NAS and ICRP (and our Federal Guidance
Report 13). ICRP cautions, however, that "Doses and risks, as measures of health
detriment, cannot be forecast with any certainty for periods beyond around several
hundreds of years into the future... Such estimates must not be regarded as predictions of
future health detriment." (ICRP Publication 81, "Radiation Protection Recommendations as
Applied to the Disposal of Long-Lived Radioactive Waste," Docket No. EPA-HQ-OAR-
2005-0083-0417, Paragraph 41) We have selected the 100 mrem/yr long-term dose
standard based on the wide acceptance of that level as a protective public dose limit and
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find that its associated risk will also protect public health and safety. Emphasizing that the
questionable assumption that current risk estimates can be applied to the very far future
calls for caution in such matters, we estimate the nominal annual risk of fatal cancer
associated with 100 mrem/yr to be 5.75 x 10"5, which is comparable to the range of risks
represented by domestic and international regulations that NAS suggested EPA consider,
and which NAS stated were "consistent with recommendations from authoritative radiation
protection bodies". (NAS Report p. 49 and Tables 2-3 and 2-4) We do not believe it is
appropriate to view this longer-term standard from within the Agency's traditional risk-
management framework (which is typically applied to situations where results can be
confirmed, modeling is utilized on a more limited scale, or institutional controls are more
applicable).
We have, however, found it useful to relate the 10,000-year individual-dose standards in 40
CFR parts 191 and 197 to the Agency's risk range (and the NAS "starting point" for our
Yucca Mountain standards), while remaining cognizant of the limitations of such
comparisons. ICRP also suggests that it is not unreasonable for shorter-term assessments
to relate dose or risk to health effects: "To evaluate the performance of waste disposal
systems over long time scales, one approach is the consideration of quantitative estimates
of dose or risk on the order of 1000 to 10,000 years. This approach focuses on that period
when the calculation of doses most directly relates to health detriment..." (ICRP
Publication 81, Paragraph 71) See Section 2, Issue H, and Section 5 of this document for
more discussion of the impacts of radiation.
Rather than as a direct measure of health impact, risk has been employed in long-term dose
assessment primarily as a mechanism to explicitly evaluate the potential impacts of low-
probability events and processes, which have the potential to contribute to exposures of
greater significance. We believe this was the significance of the NAS recommendation to
establish a risk standard. Our requirement for the probabilistic calculation of doses
effectively incorporates the issue of risk as recommended by NAS.
Commenter 0174 points out that no other EPA regulations cover periods beyond 10,000
years, concluding that any level of regulation for longer periods is stricter than for any
other activity or contaminant. Although they did not offer specific recommendations,
Commenters 0186 and 0340 were in general agreement with our position that it is
reasonable to set longer-term criteria that are higher than the level applied for 10,000 years.
Commenters 0185, 0201, and 0352 note that 350 mrem/yr represents a lower risk than
many activities routinely engaged in by the public. Commenter 0211.7 similarly suggests
that public risks are insignificant compared to risks borne by workers at nuclear power
plants or would be borne by workers at Yucca Mountain. While such comparisons can
provide important perspective, their utility may be limited and complicated by questions of
the voluntary nature of the exposure or whether compensation is offered for assuming
greater risk (e.g., for workers).
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Comment 0352-26 supports our proposal and notes that early studies of the geologic
disposal concept (including EPA's original rulemaking for 40 CFR part 191) concluded
that doses in the range of several rem per year would be possible in the event of
consumption of ground water near the repository. The commenter points out that such a
possibility did not disqualify the concept as a focus of national policy, and concludes that a
long-term dose limit of 15 mrem/yr would in effect be changing the basis for national
policy by discounting the inherent nature of the selected option. As the commenter
suggests, in both our 1985 and 1993 rulemakings for 40 CFR part 191, we emphasized that
the 10,000-year compliance period for both the containment requirements and individual-
protection limit would lead to a combination of site characteristics and engineered barriers
that would be capable of providing containment and isolation of the waste for these long
periods of time. We did not, however, anticipate that such performance could be
maintained indefinitely. Our generic technical analyses, in fact, suggested that significant
releases and doses to individuals could result at later times, depending on the
characteristics of the site in question and the presumed location of the receptor (to help
mitigate such a possibility, we included the concept of a controlled area, which is
considered part of the natural geologic barrier and inside which compliance with dose
standards will not be assessed and need not be demonstrated). For example:
The Agency examined potential doses to individuals, considering various
times in the future, from waste disposal systems in several different geologic
media. In most of the cases studied, radionuclide releases resulting in
exposures to individuals did not occur until more than 1,000 years after
disposal due to the containment capabilities of the engineered barrier
systems. Beyond 1,000 years, but prior to 10,000 years, as the engineered
barriers begin to degrade, releases resulting in doses on the order of a few
rems per year appeared for some of the geologic media studied. For other,
better geologic media, the Agency's generic analyses estimate no releases
for 10,000 years. The Agency believes that selecting a 10,000-year time for
the requirements, rather than a 1,000-year time frame, will encourage the
selection of better sites and/or the design of more robust engineered barrier
systems capable of significantly impeding radionuclide releases. These
actions, in turn, will serve to reduce the individual risks associated with the
disposal of radioactive waste.
58 FR 66401, December 20, 1993.
As the commenter noted, sites whose natural features did not provide total containment
were not necessarily considered unsuitable, but we recognized that in those instances, the
focus would have to be on "the design of more robust engineered barrier systems capable
of significantly impeding radionuclide releases." We believe that it is unrealistic to assume
that these sites would then exhibit better performance after the failure of those barriers than
they would in the initial 10,000-year period. Consequently, we believe the potential for
doses higher than 15 mrem/yr to individuals in the far future has always been implicit in
the concept of geologic disposal. Over time, the initial static system consisting of intact
waste packages and other engineered barriers in the natural geologic setting gives way to a
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more dynamic system in which episodic and gradual processes combine to transport
radionuclides to the accessible environment. The sequence and timing of barrier failures
strongly influence, and introduce considerable uncertainty into, the timing and magnitude
of projected doses over the 1 million-year period. The range of projected doses widens
considerably as the containment capability of the engineered barriers diminishes.
Interpreting the safety of the disposal system for regulatory purposes, in our judgment,
involves more than comparison of projected doses to a regulatory standard, and a standard
applicable to the initial static system would not adequately capture the essential nature of a
system that has evolved over 1 million years.
In further response to Comment 0352-26, our responsibility under the EnPA is to set public
health and safety standards for the Yucca Mountain disposal system. We view this as
neither expediting nor impeding the development of the disposal system. Moreover, we
view such considerations as improper in the context of the regulatory scheme set forth in
the EnPA. EPA's role is to promulgate, by rule, standards to protect public health and
safety from releases from radioactive materials stored or disposed of in the repository at
Yucca Mountain. Any consideration as to whether such standards are favorable or
unfavorable in the context of the NRC licensing proceeding would be inappropriate.
Section 2 Dose Limits
Issue C: Extend 15 mrem CEDE/vear to time of peak dose
1. The weaker standard would allow Nevadans to be exposed to approximately 25 times
more radiation than the previous standard, and hundreds of times more radiation than
people living next to a nuclear power plant. This is an unacceptable public health standard
and would needlessly put Nevadans at risk. (Comment 0111-1)
2.1 write to express my distress at the dangerous level of radiation allowed in the proposed
standards for Yucca Mountain. I believe they do not adequately protect the health of
humans in the area. This land is a resource that should be respected an treasured for the
future. (Comment 0119-1)
3.	EPA's recently revised standard, however, fails to comply with the court ruling and the
intent of the NAS recommendations. Instead of extending the 15 mrem/yr limit through the
time of peak risk, EPA has proposed a two part standard - 15 mrem/yr for 10,000 years,
and then a 350mrem/yr standard thereafter (up to a million years). (Comments 0126-3 and
0127-3)
4.	The only standard that will provide health and environmental protection is 15 mrem
CEDE/yr until the time of peak dose. (Comments 0133-3, 0134-1, 0135-3, 0137-3, 0144-2,
0146-3 0147-3, 0148-3, 0149-2, 0150-2, 0159-3, 0160-2, 0163-3, 0164-2, 0165-1, 0182-1,
0188-1, 0189-1, 0190-2, 0192-1, 0257-7, 0260-2, 0262-2, and 0327-2)
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5.1 am disappointed in the proposal to allow 350 mrem/yr radiation in a mere 10,000 yrs at
Nevada's Yucca site. (Comment 0153-1)
6. Current standards of 15 mrem per year from all pathways, and 4 mrem per year from
drinking water, must be applied for the full regulatory period of peak radiation doses
(hundreds of thousands of years into the future and beyond). (Comments 0175-3 and
0177-3)
7.1 am puzzled and shocked at the rationale used to support the proposed dose limit of 350
millerems/yr as the dose limit for releases from the dump. If you can make decisions about
what is safe at one point and say it is 15 and that is supposed to be ok, how can you then
say 350 is ok at another time when you have no evidence that people will become less
susceptible to radiation. What is acceptable should stay the acceptable limit regardless of
time and that is 15. (Comment 0259-1)
8.	EPA can exercise its profound mandate to serve as a "trustee to protect the interest of
future generations" by adopting a single standard that we and our grandchildren would be
willing to live with. The 15 mrem/yr standard is a laudable target. That would send this
project where it belongs—back to the drawing board. Let's take the time, do the science,
grow the technology, carry on the societal discussions, and do it right. (Comment 0267-9)
9.	The 15 mrem/yr dose limit should be imposed through the period of peak risk, which is
more like 300,000 years (according to DOE's calculations), and the Safe Drinking Water
Standard should also extend through this period. (Comment 0268-2)
10.	We urge EPA to adopt instead, a single, uniform protection standard for the entire
projected life of the proposed repository, before and after 10,000 years: 15 millirem per
year maximum exposure threshold. (Comment 0275-1)
11.	The 15 mrem/yr dose limit should be imposed through the period of peak risk, which is
more like 300,000 years (according to DOE?s calculations). (Comment 0289-3)
12.	EPA's proposed rule exceeds the National Academy of Sciences' recommended
acceptable range of risk of radiation exposure, which is 2 to 20 millirems per year, and the
NRC's radiation health standard for low-level radioactive waste disposal sites, which is 25
millirems per year. (Comment 0293-10)
13.	A4NR opposes all changes proposed in this rule for the post-10,000 year period. Like
NNTFI, we "believe that the only radiation standard for Yucca Mountain that would
provide health and environmental protection would be a rule that extends the existing
allowable dose of 15 millirem/yr to the time of peak dose, whenever it occurs, and retains
the groundwater protection standard of 4 millirem/yr." There is no justification for
establishing a two-tiered standard or for allowing any greater risk to life in the future."
(Comment 0294-4)
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14.1 urge EPA to adopt a consistent, protective rule that is not arbitrary and capricious.
EPA has said 15 millirem per year is the appropriate standard; that should be the standard
then throughout the lifetime of the proposed Yucca project. There is no sensible basis to
require such a standard during the initial period, when the project appears able to meet the
standard, and then a grossly more lax and unprotective standard thereafter, just because the
project isn't safe enough to meet a consistently protective requirement. (Comment 0296-9)
15.	EPA's proposed rules should be revised to keep radiation exposure limits to less than
15-25 millirem/year, as long as the stored nuclear waste remains toxic to human health. In
addition, the EPA should enforce a separate groundwater protection standard of less than 4
millirem/year for the period beyond 10,000 years. (Comment 0301-12)
16.	We urge EPA to adopt instead, a single, uniform protection standard for the entire
projected life of the proposed repository, before and after 10,000 years: 15 millirem per
year maximum exposure threshold, coupled with the 4 millirem groundwater protection
standard. (Comment 0303-1)
17.1 agree with the positions recommended by the State of Nevada and by the Nevada
Nuclear Waste Task Force. The State of Nevada opposes the proposed EPA rule, and has
recommended instead that EPA: "extend the 15 millirem per year maximum exposure
threshold, together with the 4 millirem groundwater protection requirement, through the
period of maximum projected releases for the Yucca Mountain facility." (Comment 0304-
1)
18.	The only scientifically and legally supportable way to bring EPA's Yucca Mountain
rule into compliance with the Court's directives and the NAS recommendations is to extend
the 15 millirem per year maximum exposure threshold, together with the 4 millirem
groundwater protection requirement, through the period of maximum projected releases for
the Yucca Mountain facility. (Comment 0309-3)
19.	The period of compliance for the 15 mrem/yr and the 4 mrem/ ground-water standard
must be continued through the time to peak dose. (Comment 0311.1-4)
20.	There is no reason that EPA could not have required that a singular protective standard
be required for the life of the repository, reliant on the modeling associated with the
geologic conditions and stability. Indeed, that is precisely the action NAS recommended
that EPA take in estimating maximum doses from releases of radionuclides. (Comment
0311.1-12)
21.	EPA errs in setting a standard so high especially given the overlooked uncertainties
associated with the decision. I urge the EPA to consider a more cautious approach and
maintain the 15 mrem/year standard throughout the compliance period, a peak dose level
that was also considered by the EPA (Section II.C.4.a.). The proposal states that "...a
compliance standard on the order of 15 mrem/yr implies far more precision in projections
for very long times than can be supported and, as such, is inconsistent with the "reasonable
expectation" approach." However, the notion that".. .rising uncertainties justify adopting a
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different (higher) dose level" (Section II.C.2.b. paragraph 2) demands reconsideration. In
addition, "reasonable expectations" ought to be more broadly defined to include blatant,
presently-ignored-because-they-are-not-fully-understood uncertainties.
It appears EPA justifies the proposed standard of 350 mrem due to international guidance
and speculated natural background levels, even though the NAS recommended the standard
rely upon current conditions rather than speculation. Furthermore, the EPA states in
Section II.C. 1. that "no regulatory body that we are aware of considers doses of 150 mrem
to be acceptable." Therefore, according to the Agency itself, 350 mrem is an unacceptable
standard. It is more than three times the quantity allowed from nuclear facilities today by
the Nuclear Regulatory Commission. (Comment 0312.5)
22.	The annual dose limit for all pathways should be between 10 and 25 millirem and
should remain constant in time over the period of geologic stability at the site. A separate
sub-limit of 4 millirem per year to the most exposed organ from the drinking water
pathway should be included over the entire period of geologic stability. (Comment 0314.1-
8)
23.	The far more generally applied level of "acceptable" risk of 10"5 to 10"6 should serve as
the basis for determining whether future generations are being given at least the same level
of protection as is considered acceptable for the present generation. This choice is
consistent with the conclusions of both the International Commission on Radiological
Protection and the International Atomic Energy Agency which have both recommended
using a risk equivalent of 10"5 per year as a reference value in setting limits for the geologic
disposal of high-level waste. (Comment 0314.1-12)
24.	NIRS again submits on behalf of the 2,000 petition signers in the year 1999, as well as
on behalf of its members across the U.S., that EPA's fullest protections must be applied not
only for the first 10,000 years at Yucca, but through the period of peak dose (to live up to
NAS recommendations) and beyond (to protect all future generations to the same standard
as current generations, the only ethical and moral position to take). The 15 mrem/yr
standard must be applied till peak dose hundreds of thousands of years into the future to
meet the legal requirements, and should extend even beyond that to meet moral and ethical
requirements. (Comments 0324-15, 0324-28, and 0324-29)
25.	On behalf of my wife, my children, and myself, I am writing in opposition to the EPA
proposed rule. We urge EPA to adopt instead, a single, uniform protection standard for the
entire projected life of the proposed repository, before and after 10,000 years: 15 millirem
per year maximum exposure threshold, coupled with the 4 millirem groundwater protection
standard. (Comment 0325-1)
26.	We recommend that the new EPA radiation protection standard should fall within
this recommended exposure range limit of 10-30 millirems per year. EPA's radiation
protection standard should be consistent with the NAS findings and recommendations. A
radiation exposure limit should be set within the recommended range of 10 to 30 millirems
per year, e.g., 15 millirems per year as recommended by EPA. (Comment 0326-2)
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27.	Citizen Alert also feels that it is necessary and important for the EPA to take a
progressive step in applying maximum exposure limits that are less than those in the
current rule, which stems from the following considerations:
•	The U.S. government is embarking upon a project that has never been tried before,
and we do not have the luxury of previous experience; only time will tell whether
this grand experiment will achieve the intended goal of waste isolation.
•	Given the current data it seems clear that groundwater contamination will occur at
some point in the future (-200,000 - 300,000 years if the DOE calculations are
reasonable), and is an irreversible process requiring hundreds of thousands if not
millions of years to decay away.
•	The shear scope of the Yucca Mountain Project in terms of the amount of waste,
intensity of the radioactivity, and longevity affords special consideration.
Otherwise, the small and possibly ignorable errors in design could be magnified
resulting in potentially enormous impact.
•	There are a number of other countries that have more stringent radiation
protection standards than we do in the United States.
What do those countries know that we don't? Perhaps, they are looking ahead and
predicting that as the body of information on the health effects of radiation expands, people
will demand tighter standards. Certainly, the history of exposure standards in this country
reveals a trend toward lower allowed exposure in nuclear facilities and the general public.
For these reasons it is necessary to have that extra margin for error. What if we are wrong,
and the models don't predict as expected? To be sure, we have been wrong before: the
Titanic, Exxon Valdez, the Challenger, need we go on? Citizen Alert strongly urges the
EPA to build in that extra "cushion" for the protection of all U.S. citizens. (Comments
0268-7 and 0328-6)
28.	The City believes that the EPA should extend the 15 millirem per year standard through
the period of maximum projected releases for the Yucca Mountain facility. (Comment
0341-1)
29.	Eureka County believes that the radiation standard should be reasonable and protective
in the near and far term, and that the proposed standard does not accomplish that goal. In
order ensure that the radiation standard is protective, EPA should extend the 15 millirems
per year maximum exposure threshold together with the 4 millirem groundwater protection
requirement to apply throughout the period of maximum projected releases for the Yucca
Mountain facility. EPA should withdraw the proposed rule and issue a draft standard that is
protective through the period of maximum projected releases at Yucca Mountain.
(Comments 0353-10 and 361-10)
30.	The proposed 40 CFR 197 provides a level of protection for the first 10,000 years after
the repository is closed, and less for those people who will be living after 10,000 years. In
fact, the all pathway standard is weakened by a factor of approximately 24, and the
groundwater standard is eliminated. The 15 millirem per year dose limit should be imposed
through the period of peak risk, which, according to DOE's own calculations is more like
300,000 years. The Safe Drinking Water Standard should also extend through this period.
(Comment 0354-5)
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31.	EPA's proposal to allow 350 millirem per year radiation doses to people living
downstream from the leaking dump - the equivalent of 58 full chest x-rays per year - would
not only cause cancer, but also birth defects, genetic damage, and other maladies, and at
alarming rates, and must be withdrawn. Current standards of 15 millirem per year from all
pathways, and 4 millirem per year from drinking water, must be applied for the full
regulatory period at Yucca Mountain, extending to the period of peak radiation doses
(hundreds of thousands of years into the future) and beyond. (Comments 0310-2 and 0355-
2)
32.	EPA should err on the side of caution ands use the present limit (15 millirems per year)
as the standard for protecting the health and safety of people and the land now and in the
future. (Comments 0360-4 and 0363-4)
33.	Making this hard by fighting for the 15 mR - the burden of proof should be on DOE.
(Comment 0367.1-20)
34.	... we urge you to revise the proposed rules, to keep radiation exposure limits to less
than 15 to 25 millirems per year. (Comment 0368.2-6)
35.	.. .I'd like to be sympathetic to EPA ..., although I think the EPA found a wrong
solution for it, is how do you deal with the questions of hundreds of thousands of years
from a technical point of view. And I would like to suggest that it's not in the relaxation of
the standard. ... let me recommend a specific alternative ... for a standard which would be
somewhere between 10 and 25 millirem for the effective dose equivalent per year from all
pathways with a sublimit for four millirem per year from drinking water. (Comment
0368.3-2)
Response to Issue C:
After considering public comments, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) as the individual-protection standard to apply for the period between 10,000
years and 1 million years. Instead, we are establishing 1 mSv/yr (100 mrem/yr) as the
individual-protection standard applicable beyond 10,000 years. This level is widely
accepted and recommended, both internationally and domestically, as a protective overall
public dose limit for practices involving the use of radioactive material. We will, however,
address the comments that supported extending the 150 [j.Sv/yr (15 mrem/yr) dose standard
throughout the compliance period.
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A significant number of commenters disagreed with our proposal and recommended simply
extending the 15 mrem/yr standard at least through the time of peak dose. Many of these
commenters also recommended extending the ground-water protection standards (we refer
those commenters to Section 12 of this document). Commenters frequently cited the
difference in protectiveness between the two levels as cause for concern. Some
commenters argued that our proposal does not satisfy the Court ruling or the NAS
recommendation. Commenters also touched on the issue of intergenerational equity, which
we address in Section 9 of this document.
Comment 0259-1 questioned our reasoning that 350 mrem/yr is protective at very long
times when we have not argued that humans will be less susceptible to radiation. It is true
that we neither make this argument, nor do we consider that new information on radiation
effects will result in tighter standards, as comment 0328-6 suggests. The RMEI is a
hypothetical person representative of today's population in Amargosa Valley, and no
changes in society, biology, or technology have been assumed. Our reasoning is that the
increasing uncertainties in projecting releases over periods of several hundred thousand
years justify modifying these numerical performance indicators to recognize this changing
context. Comment 0355-2 states that "alarming rates" of health effects would result from
our proposed standard. Our final long-term dose standard of 100 mrem/yr is protective of
public health and safety (see Issue H of this section as well as Section 5 of this document
for discussion of health risks from radiation). Our final standard is assessed against
calculated doses to a person who is among the most highly exposed members of the
population. Population patterns, lifestyles, and characteristics of potential contaminant
pathways lead us to conclude that the majority of the population would be exposed at much
lower levels than the RMEI, if at all.
We disagree with Comments 0126-3, 0127-3, 0293-10, 0296-9, 0309-3, 0311.1-12, 0324-
15, 0324-28, 0324-29, and 0326-2, which claim that our approach is not consistent with
either the D.C. Circuit decision or the NAS recommendation. As we noted in our proposal
(70 FR 49021-49022), the Court ruled only that our standard was not consistent with the
NAS recommendation to require compliance assessment at the time of peak dose. The
Court vacated our standard "to the extent that it incorporates a 10,000-year compliance
period." Nuclear Energy Institute v. Environmental Protection Agency, 373 F.3d 1251,
1315 (D.C. Circuit 2004). Therefore, in accordance with the recommendations of the
National Academy of Sciences, we have established a peak dose standard together with a
compliance period of 1 million years. We have addressed our original policy concerns
regarding the use of very long-term projections as a licensing criterion by proposing a
revised standard containing a higher compliance limit for very long times, as well as other
requirements related to performance assessment and compliance determination. We
believe we have addressed those policy concerns in a manner consistent with the findings
and recommendations in the NAS Report. Our final standards are protective of public
health and safety, meaningful, implementable, and provide a reasonable test of the disposal
system that is consistent with the NAS Report, D.C. Circuit decision, and the principles of
reasonable expectation.
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The NAS Report recognized the possible outcome of a rulemaking establishing a dose
standard that changed over time; however, we believe this approach is consistent with the
intent of the committee. The committee acknowledged the possibility of "some other"
approach than "a health-based risk standard... specified to apply uniformly across time and
generations" in its discussion of intergenerational equity. (NAS Report pp. 56-57) (See
Section 9 of this document and the preamble to the final rule for more discussion of
intergenerational equity.) The NAS committee recommended only that compliance be
assessed at the time of peak risk, stating "that there is no scientific basis for limiting the
time period of the individual risk standard to 10,000 years or any other value." (NAS
Report p. 55) NAS did identify a range of risks represented by current national and
international regulations, "all of which are consistent with recommendations from
authoritative radiation protection bodies," for EPA to consider. (NAS Report p. 49 and
Tables 2-3 and 2-4) Our 10,000-year dose rate limit of 15 mrem/yr is consistent with the
range of risks identified by NAS, and we point out that none of the regulatory precedents
considered by NAS applied for periods approaching 1 million years. (NAS Report p. 45)
The NAS committee explicitly declined to recommend a risk or dose level, recognizing that
as "not ultimately a question of science but of public policy." (NAS Report p. 5) Further,
NAS noted that the final outcome of the rulemaking might diverge substantially from the
starting point suggested by NAS: "Finally we have identified several instances where
science cannot provide all of the guidance necessary to resolve an issue.. .In these cases, we
have tried to suggest positions that could be used by the responsible agency in formulating
a proposed rule. Other starting positions are possible, and of course the final rule could
differ markedly from any of them." (NAS Report p. 3, emphasis added) Thus, we agree
with NAS that the selection of a level for the peak dose standard is one of the regulatory
policy issues left to EPA's discretion by the EnPA. The 100 mrem/yr peak dose standard is
comparable to the range of risks suggested by NAS for EPA's consideration. The nominal
annual risk of fatal cancer associated with 100 mrem/yr, 5.75 x 10"5, is reasonable when
significantly extended time frames are taken into account, and the considerable
uncertainties in projecting performance for up to 1 million years are considered.
Further, we believe NAS understood that dose projections would effectively become
increasingly stylized as the time period covered by the assessments increased, and that a
compliance standard applicable for times approaching 1 million years might be different in
some important respects from its recommendations. For example, NAS acknowledged that
"it is obviously impossible to predict in detail either the nature or the timing of future
climate change" (NAS Report p. 77), and the committee's frequent references to
"bounding" and other approaches reflect its concern that effectively addressing long-term
uncertainties would be critical in implementing compliance assessments over periods of
this length, (e.g., NAS Report pp. 9, 19, 20, and 79) NAS's statement that "the final rule
could differ markedly from" the starting point implicitly acknowledges that there might be
valid reasons for departing from standards we (and others) had previously established for
much shorter time frames. (NAS Report p. 49) Indeed, NAS noted a similar consideration
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in reaching its recommendation, stating that "selecting a time scale for analysis involves
weighing how the scientific basis for analysis changes with time against the timing at
which more numerous future health effects are likely to occur." (NAS Report pp. 30-31)
We believe it is reasonable to consider not only how the scientific basis for the analysis
changes, but also the demands of the regulatory process, in making the policy selection of a
long-term peak dose standard applicable for times as long as 1 million years. More
discussion on this point may be found in Issue G of this section.
We note that Mr. Robert Fri, who chaired the NAS committee, testified in his personal
capacity before the Senate Environment and Public Works Committee on March 1, 2006
(oral testimony at Docket No. EPA-HQ-OAR-2005-0083-0380, pp. 54-58, prepared
statement at Docket No. EPA-HQ-OAR-2005-0083-0402). His testimony, which
paralleled presentations he has given in other venues, focused on the relationship between
the time frame of regulation and the characteristics of the receptor identified in that
regulation. Mr. Fri pointed out that the committee had recommended the use of a
probabilistic critical group, which it felt would be less "deterministic" and conservative
than the "any member of the public" standard in our generic regulations at 40 CFR part
191. We chose instead to identify the more conservative1 reasonably maximally exposed
individual (RMEI), which the committee commented in 1999 was "broadly consistent"
with the goals of the probabilistic critical group (66 FR 32089, Docket No. EPA-HQ-OAR-
2005-0083-0042). Mr. Fri testified that the combination of the RMEI (although in his view
still "deterministic") and the 15 mrem/yr dose limit was a reasonable approach for the
initial 10,000-year period. However, he cautioned that maintaining the RMEI as the
receptor while extending the compliance period up to 1 million years put us in a position
where "the Committee did not want to be" because it led to a level of conservatism with
which the committee was not comfortable. He noted that one committee member had
recommended such an approach, which was rejected by the committee (see pp. 100-103
and Appendix D of the NAS Report for this alternative view) as having the potential to
"become just such an extreme case." (NAS Report p. 188) Mr. Fri's testimony stated that,
while he could not say whether the 350 mrem/yr proposal would be consistent with the
NAS recommendation, he believed it was intended to remove some of the conservatism
(i.e., in his view it had the effect of moving us in the direction toward where the committee
"wanted" us to go). This leads us to conclude that the approach we have taken in
proposing a higher dose limit for longer times could be more consistent with the NAS
recommendation than would be a 15 mrem/yr dose limit throughout the period of geologic
stability.
Comments 0268-7 and 0328-6 raise a number of interesting points to conclude that the
dose limit should remain at 15 mrem/yr beyond 10,000 years. Several of the points touch
on the critical aspect of geologic disposal, which is the assumption that direct observation
of the system will not be possible over the times when releases are most likely to occur.
1 In considering a proposed subsistence-farmer critical group as an alternative to its preferred probabilistic
critical group, the committee noted that "it makes the most conservative assumption that wherever and
whenever the maximum concentration of radionuclides occurs in a ground water plume accessible from the
surface, a farmer will be there to access it." (NAS Report p. 102) The RMEI incorporates this "most
conservative assumption."
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The commenter suggests that "only time will tell whether this grand experiment will
achieve the intended goal of waste isolation" - however, that must always be the case.
Mathematical modeling is the only method available to project the overall system
performance on geologic timescales, although other arguments need to be made to provide
context and confidence in the approach taken to projections, and these other arguments
may in fact become more important in decision-making as the time period covered by the
assessment increases. As noted by NAS, the "results of compliance analysis should not,
however, be interpreted as accurate predictions of the expected behavior of a geologic
repository" over such times, and in fact must be viewed more as indicators of system
performance. (NAS Report p. 71)
The commenter further states that the scale of Yucca Mountain means that "small and
possibly ignorable errors in design could be magnified resulting in potentially enormous
impact" and points to the Titanic, Exxon Valdez, and Challenger as justifying an "extra
margin for error" if the models are not correct. However, our concerns regarding long-term
modeling relate to the emphasis that such projections should be given in compliance
decision-making, and are not tied specifically to DOE's ability to construct appropriate
models. We do agree with the commenter regarding the propagation of error. Many
commenters in later sections cited DOE's estimates of waste package performance as a
critical factor that remains unproven. However, the effects of such design flaws or
modeling errors are essentially unknowable, and in some cases might result in improved
performance or overestimated releases. That is why we believe that judgments to be made
by NRC prior to licensing regarding aspects of DOE's program such as quality assurance,
performance confirmation testing, site characterization, and basic modeling assumptions
may be as important, if not more important, than doses projected to occur several hundred
thousand years after disposal. (See Docket No. EPA-HQ-OAR-2005-0083-0376, p. 45, for
considerations in NRC's evaluation of "reasonable expectation.")
Finally, the commenter states that "there are a number of other countries that have more
stringent radiation protection standards than we do in the United States." We presume this
refers to our Yucca Mountain proposal for the peak dose standard beyond 10,000 years,
and not to other radiation protection regulations, including the 15 mrem/yr standard
applicable for the initial 10,000 years at Yucca Mountain. While we address this issue in
more detail in Section 4 of this document, we note that the more typical approach
internationally is to require compliance with quantitative performance assessment for only
a limited period of time (in some cases, less than 10,000 years). Longer-term dose
projections may be compared to dose or risk targets or reference levels, but are viewed
more as qualitative indicators of performance, to be weighed in conjunction with other
qualitative arguments for confidence in the overall safety of the facility.2 Non-compliance
2 The 2006 NEA document on "Consideration of Timescales in Post-Closure Safety of Geological Disposal of
Radioactive Waste," which is based on surveys of NEA Member Countries, states "Calculated values of dose
and risk are therefore viewed in regulations not as predictions but rather as indicators or measures of
protection that are used to test the capability of the system to provide isolation of the waste and containment
of radionuclides (the 'dose' that is being calculated is what radio-protectionists refer to as 'potential dose').
These indicators are to be evaluated on the basis of models that include certain stylized assumptions, in
particular regarding the biosphere and human lifestyle or actions." (p. 38) NEA also notes: "There is
agreement that calculations of dose and risk in the future are illustrations of possible system behaviour rather
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with the dose or risk criteria in such cases is not necessarily cause for rejection of the safety
case, unlike in our rule. The weight given to quantitative projections typically decreases as
the time frame gets longer. Comment 0314.1-12 touches on the same issue in pointing out
that an annual risk level of 10"5 to 10"6 "is consistent with the conclusions of both [ICRP]
and [IAEA] which have both recommended using a risk equivalent of 10"5 per year as a
reference value in setting limits for the geologic disposal of high-level waste." We believe
the term "reference value" is instructive, as both organizations indicate that projected doses
that would be unacceptably high in the initial period after disposal because they would
exceed the regulatory standard (or "constraint") would not necessarily be unacceptable at
longer times. ICRP states that "as the time frame increases, some allowance should be
made for assessed dose or risk exceeding the dose or risk constraint. This must not be
misinterpreted as a reduction in the protection of future generations and, hence, a
contradiction with the principle of equity of protection, but rather as an adequate
consideration of the uncertainties associated with the calculated results" (Publication 81,
"Radiation Protection Recommendations as Applied to the Disposal of Long-Lived Solid
Radioactive Waste," Docket No. EPA-HQ-OAR-2005-0083-0417). Similarly, IAEA
states: "In very long timeframes.. .uncertainties could become much larger and calculated
doses may exceed the dose constraint. Comparison of the doses with doses from naturally
occurring radionuclides may provide a useful indication of the significance of such cases."
("Safety Requirements for Geological Disposal of Radioactive Waste," WS-R-4, Docket
EPA-HQ-OAR-2005-0083-0383, paragraph A.7, p. 37) We attempted such an approach in
our 2001 rulemaking, which gave NRC flexibility to consider longer-term dose projections
as it thought appropriate within the licensing process (i.e., NRC would decide how much
meaning or weight should be assigned to those projections).
Comment 0312.5 disagrees with our rationale for a higher standard, and expresses concern
that "overlooked uncertainties" may be more important and should be included in the
determination of "reasonable expectation." See Sections 6 and 17 of this document for
more discussion of these aspects of our decision. The commenter also states that we appear
to have relied upon "speculated natural background levels, even though the NAS
recommended the standard rely upon current conditions rather than speculation." Our
discussions of background radiation have been in the context of existing data, and we have
not attempted to project background radiation through the period of geologic stability, as
some comments suggested we should. Regardless, we have not used specific estimates of
than predictions of outcomes, and there is consensus that, in the long term, numerical criteria for radioactive
waste disposal should be considered as references or indicators, addressing the ultimate safety objectives,
rather than as absolute limits in a legal context." ("Regulating the Long-Term Safety of Geological Disposal:
Towards a Common Understanding of the Main Objectives and Bases of Safety Criteria," NEA-6182, Docket
No. EPA-HQ-OAR-2005-0083-0408, p. 24) Similarly, ICRP Publication 81 contrasts the approach of
"consideration of quantitative estimates of dose or risk on the order of 1000 to 10,000 years" with
"consideration of quantitative calculations further into the future making increasing use of stylized
approaches and considering the time periods when judging the calculated results. Qualitative arguments
could provide additional information to this judgmental process." (Paragraph 71) The IAEA consensus
document for geologic disposal ("Safety Requirements for Geological Disposal of Radioactive Waste," WS-
R-4, 2006) states: "It is recognized that radiation doses to individuals in the future can only be estimated and
that the uncertainties associated with these estimates will increase for times farther into the future. Care
needs to be exercised in using the criteria beyond the time when the uncertainties become so large that the
criteria may no longer serve as a reasonable basis for decisionmaking." (Paragraph 2.12)
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background radiation to derive our final peak dose standard. Finally, the commenter notes
that the proposed peak dose limit is higher than that allowed from currently operating
nuclear facilities. The final peak dose standard we are establishing, 100 mrem/yr, is the
NRC's public dose limit applicable to individual licensed operations today (10 CFR
20.1301), although lower dose constraints apply to certain types of operations. However,
we do not believe it is necessarily reasonable to compare the basis of regulatory limits for
operating facilities, where active measures can be taken, with those established for a
passive disposal system for which peak doses may occur at times approaching 1 million
years into the future. Commenter 0293-10 makes a similar point in noting that the NRC
standard for low-level radioactive waste disposal facilities in 10 CFR part 61 is 25
mrem/yr. However, the time frame of concern for these near-surface facilities is closer to
the 10,000-year compliance period we originally established in our 2001 rulemaking.
Limits on the concentrations of long-lived transuranic or other highly mobile radionuclides
help to ensure that projected doses remain low. See also Issue G of this section for
discussion of apportionment of potential doses among multiple sources.
Section 2 Dose Limits
Issue D: Reduce the dose limit below 15 mrem/yr
1.1 urge you to reverse the decision to allow radioactivity from Yucca Mountain to come in
contact with the environment and its people. Most recently the National Academy of
Sciences came out with study results that indicated that no amount of radiation was good
for people. The amounts that the EPA is willing to expose people to are far too high.
(Comment 0158-1)
2.	The EPA's dose limits for the 10,000 years after closure are within the range of most
countries of 10-30 millirem per year is too high for the amount of radiation exposure we
are encounter through a year. Exposure from living next a nuclear power plant is 1 millirem
per year. With the increasing sources of natural and man-made produced radiation, the EPA
should consider a lower threshold for the Yucca Mountain Project for the overall
acceptable emission to 5-10 millirem per year for the first 10,000 years after the closure of
the repository. (Comment 0265-1)
3.	EPA should instead adopt a standard that limits exposure to less than the minimum
exposure standard proposed by any body world wide. (Comment 0275-3)
4.	Even a dose level of 15 millirem per year, which would be in addition to other sources, is
impermissible if future public health is to be protected from high-level waste radiation
damage. (Comment 0331-1)
5.	Apart from the role of EPA in determining human exposure standards from the time of
repository closure to 1,000,000 years, EPA indicates that much decision-making latitude
will be permitted for DOE and NRC in a Yucca Mountain licensing process, if there is one.
For that reason, it is imperative that EPA exercise its standards-setting responsibility with a
maximum of precaution, revising downward toward zero exposure. (Comment 0331-8)
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6. No risk is acceptable. No Nevada resident wants to live near a nuclear dump. (Comment
0367.2-16)
Response to Issue D:
Comments in this section generally expressed the opinion that our individual-protection
standard should be lower than the 15 mrem/yr level established for the initial 10,000 years
after disposal. Comment 0158-1 points to the BEIR VII study as concluding "that no
amount of radiation was good for people." (Docket No. EPA-HQ-2005-0083-0430)
Comment 0331-1 similarly takes the position that 15 mrem/yr is insufficiently protective of
public health. In response to the first comment, the BEIR VII study concluded that there is
insufficient evidence to support the concept of a "threshold" below which radiation
exposure conveys no risk, or that such risks are not proportional to the exposure (e.g., if the
exposure doubles, the risk also doubles). EPA and other regulatory bodies continue to
apply the "linear no threshold" approach in radiation protection. However, the BEIR VII
committee did not conclude that radiation exposure conveys no benefits to consider against
the potential risks. The 15 mrem/yr level is consistent with the Agency's overall risk
range, has been successfully implemented for periods of 10,000 years, and is protective of
public health. See Issue H of this section, as well as Section 5, for more discussion of the
health aspects of radiation in general and our standards in particular.
Several other comments supported a lower standard, but for other reasons. Comment 0265-
1 suggests revising the standard to account for "increasing sources of natural and man-
made produced radiation," suggesting instead a level of 5 to 10 mrem/yr. Our mandate
under the EnPA is to address releases of radionuclides from the Yucca Mountain disposal
system. The standards we have established to address that specific source of radiation are
protective of public health and the environment. We do not believe it is useful to speculate
about the potential increase (or decrease) in radiation from other sources that may take
place over the next several thousand years. See Issue N of this section for more discussion
of other sources of radiation.
Comments 0275-3 and 0331-8 express skepticism about performance assessment modeling
and the NRC licensing process. Commenter 0275 considers modeling to be unreliable and
therefore recommends the standard be "less than the minimum exposure standard proposed
by any body world wide," as well as more stringent in other ways, such as comparing the
95th percentile value of projected doses to the dose standard. Commenter 0331 views NRC
as having too much latitude in decision-making. A lower standard would indicate a
"maximum of precaution" on our part. We do not believe the commenters' suggestions are
appropriate. Modeling is the primary tool available to estimate performance over very long
time frames, and its capabilities must be considered along with its results. We agree that
there are limitations to performance modeling, but do not agree that the emphasis should
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then be on extreme situations, which we believe would result from the first commenter's
approach. Nor do we believe such an approach would be consistent with the intent of the
NAS committee (see Issue C of this section and Section 7). Further, the limitations in
providing "proof' of performance for periods of 10,000 years or longer have been widely
recognized, leading to our adoption of the "reasonable expectation" principle. NRC does
have latitude in reaching that determination, which it will have to defend in adjudicatory
proceedings. Reasonable expectation also discourages reliance on extreme assumptions,
whether conservative or optimistic. See Section 17 of this document.
Finally, Comment 0367.2-16 implies that the dose level should be zero, since "no risk is
acceptable." We have never stated or believed that geologic disposal is expected to provide
perfect containment for all times. It has always been assumed that releases, and subsequent
exposures (assuming the presence of people whose characteristics would lead to
exposures), will occur. Our responsibility is to establish standards for such releases that
will protect public health. We do not interpret this responsibility as requiring that no
person at any time will have the potential for exposure. Further, we do not regulate any
other contaminant or activity to zero risk.
Section 2 Dose Limits
Issue E: Insufficient rationale to support the increase after 10,000 years
1.	The Environmental Protection Agency says in its explanatory statement that "Given the
increased uncertainty that is unavoidable in the capabilities of science and technology to
project and affect outcomes over the next 1 million years, the concept of reasonable
expectation underlying our standards implies that a dose limit for that very long period that
is higher than the 15 mrem/yr limit that applies in the relatively "certain" pre-10,000-year
compliance period could still provide a comparable judgement of overall safety." (Federal
Register Vol. 70, p. 49029, 2005) This justification does not make sense. If one were
designing a bridge whose steel and concrete performance became more uncertain with
time, would one loosen or tighten the structural design standards if one realized that the
bridge was going to have to provide safe transport for a longer period of time? The EPA
has not provided an adequate justification for the large relaxation in stringency of the dose
limit after 10,000 years. This comment does not address the question of whether the less-
than-10,000-year standard is too restrictive or the greater-than-10,000-year standard is too
lax. It only addresses the failure to provide a logical rationale for loosening the standard in
the face of greater uncertainty. (Comment 0167-1)
2.	Standards should not be "degraded" simply because a certain amount of time has
elapsed. If a standard is set for a legitimate reason, it should remain intact until an equally
legitimate reason is found to make an adjustment. The adjustment should be performance
based and not simply because a time limit has passed. (Comment 0223-1)
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3. With no valid explanation, EPA increased the radiation exposure limit to 350 millirems
per year after 10,000 years. Needless to say, Yucca Mountain would then meet the new
radiation standard. There is not enough evidence or a clear rational argument for not
leaving the radiation standard the same after 10,000 years. There was no overriding
rationale for lowering the standard for future generations. (Comments 0360-2 and 0363-2)
Response to Issue E:
The thrust of these comments is that uncertainty alone is not a sufficient rationale for
departing from the 15 mrem/yr standard for the 10,000 year compliance period, and that
EPA has not provided sufficient rationale for using increasing uncertainty as a justification
for establishing the peak dose limit (Comments 0360-2, 0363-2,0223-1, and 0167-1). In
response to these comments and others, the Agency performed some generalized site-
specific modeling (uncertainty analysis) to: examine the effects of uncertainty in dose
projections over the time to peak dose and gain some insight on the implications of
uncertainty in very long-term dose projections on the issue of setting a peak dose limit
(Docket Nos. EPA-HQ-OAR-2005-0083 0414 and EPA-HQ-OAR-2005-0083 0429). The
actual performance of the disposal system at Yucca Mountain may be better or worse than
that shown in our projections for a hypothetical system. One modeling exercise (Docket
No. EPA-HQ-OAR-2005-0083-0386) was performed to provide some insight on the effects
of uncertainties on a reference disposal system for the site that was at the "edge of
compliance" at the 10,000 year time, i.e., a hypothetical disposal system was set-up as a
reference starting point where the disposal system was delivering a mean dose of 15
mrem/yr at 10,000 years. The behavior of this reference case was then modeled under
expected site conditions through the time of peak dose. The details of this modeling work
and the results are contained in reports in the rulemaking docket (Docket No. EPA-HQ-
OAR-2005-0083-0386), and briefly explained below along with their implications for the
rulemaking.
The 15 mrem/yr mean dose limit was chosen as the reference case starting point for our
uncertainty analyses because it is the dose limit established in 40 CFR part 191 and is also
the 10,000-year dose limit in the proposed and final standards. Although the 15 mrem/yr
limit is in the generic standards (40 CFR part 191) originally promulgated in 1985, it was
intended to apply to any deep geologic repository site, and as such, it serves as a suitable
starting point for examination of the Yucca Mountain site. However, this dose limit was
specifically restricted to a performance period of 10,000 years in 40 CFR part 191 (as
amended in 1993), based on the belief that increasing uncertainty after that time would
reduce the credibility of such dose projections to such an extent that regulatory decision
making would become overly burdened with speculative assessments of performance (58
FR 66401, December 20, 1993). However, the NAS recommendation to set a standard at
the time of maximum risk within the period of geologic stability, and in response to the
Court's findings, the Agency has had to re-examine the question of establishing a peak
dose limit.
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With the development of long-lived waste packages and highly corrosion resistant alloys,
performance assessments of the Yucca Mountain disposal system (Docket No. EPA-HQ-
OAR-2005-0083-0085) showed that the period of maximum risk would be well beyond the
40 CFR part 191 compliance period of 10,000 years, which was also the concern expressed
by NAS. To examine both the subject of increasing uncertainty in performance projections
and the implications for setting an appropriate and protective peak dose limit, the Agency
has modeled a hypothetical Yucca Mountain disposal system that would be at the "edge of
compliance" at 10,000 years, i.e., it would be delivering a mean dose of 15 mrem/yr to the
RMEI. The analyses address the question - What would be the variations in dose
projections for a hypothetical disposal system at Yucca Mountain that was performing at
that level (mean dose of 15 mrem/yr at 10,000 years) when the time frame for the
assessments increased to peak dose. This analysis examined the effects of uncertainty in
natural barrier performance on dose projections, since the number of waste packages
deliberately failed to generate the mean 15 mrem/yr reference case starting point was held
constant for the rest of the time period to peak dose. The spread in dose estimates between
the initial 10,000-year time period and the longer period time period at peak dose were
compared to determine the effects of uncertainties on the projected doses over that time
period. These assessments were possible because of the large database of site-specific
information now available from characterization studies for the site, and the advances in
performance assessment technology since 1985 (Docket No. EPA-HQ-OAR-2005-0083-
0085).
The analyses showed that for a reference disposal system constructed to allow a mean dose
rate of 15 mrem/yr at 10,000 years as a starting point, and allowed to continue to release
radionuclides (from the fixed number of waste packages needed to result in the starting
mean of 15 mrem/yr dose rate) under the ranges of site conditions over time, the
uncertainties seen in the projections increased from 1.5 (at 10,000 years) to 3.5 orders of
magnitude at peak dose, an increase of approximately two orders of magnitude. This level
of uncertainty indicates that there is a considerable increase in the range of the dose
projections. Peak doses for various modeling choices for this hypothetical system varied
from approximately 160 to 400 mrem/yr. For a system where the early waste package
failures result in a mean dose of 15 mrem/yr at 10,000 years and additional waste package
failures continue to occur beyond that time, peak dose estimates would be considerably
higher than those for our modeling exercise where the waste package failures were not
permitted to increase after the 10,000 year time line. From this perspective, the 100
mrem/yr peak dose limit should not be regarded as a "loosening" of the 10,000 dose limit
but is actually very strict in that it constrains the disposal system to keep waste package
failure rates extremely low over long periods of time (tens to hundreds of thousands of
years) in order to keep the peak dose below the 100 mrem/yr limit. Again, the actual
performance of the disposal system at Yucca Mountain may be better or worse than that
shown in our projections for a hypothetical system, which is based on a simplified site
model that is not as complex as DOE's (Total System Performance Assessment) model.
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The fundamental premise underlying these uncertainty assessments is that the 40 CFR part
191 dose limit was limited to 10,000 years, and was not intended to imply that a repository
had to limit projected releases to that level indefinitely (see the preamble to the final
amendments and Issue B of this section for more information). Results of our analyses
address the two objectives mentioned above: (1) assessing the nature and extent of
increasing uncertainties on dose projections over time and (2) providing some insight into
the question of uncertainty in setting dose limits for the peak dose. The modeling results
show that there is a meaningful quantitative increase in uncertainty in making dose
projections.
We also examined the behavior of the Yucca Mountain disposal system with respect to
"driver" processes that control the timing and magnitude of the peak dose and the general
capability of the performance assessment tool to meaningfully distinguish between
alternative conceptualizations of the disposal system (Docket Nos. EPA-HQ-OAR-2005-
0083-0414 and EPA-HQ-OAR-2005-0083 0429). Results of these assessments illustrated
that inherent uncertainties involved with probabilistic performance assessments and the
uncertainties in data selection and scenario development for very long-term assessments
limit the ability of the performance assessment tool to distinguish between some alternative
conceptualizations of the disposal system.
Our results demonstrate that uncertainties in dose projections increase significantly over
very long time frames. This observation supports the general assumption made about
increasing uncertainties in the original 40 CFR part 191 standard. It also confirms the
general thrust of international guidance on the subject of heavy reliance on numerical dose
projections in the very long-term, referenced in the preamble to the proposed rule (70 FR
49036, August 22, 2005) and discussed in the preamble to the final rule and Section 4 of
this document. With these uncertainties in mind, the degree of confidence possible in
meaningfully distinguishing between alternative assumptions about the performance of the
natural barrier, or alternative designs for engineered barrier components, decreases
significantly over very long time frames. This increasing uncertainty makes regulatory
compliance decision making more difficult and subject to speculation. Alternative
assumptions about natural barrier performance reflected in alternative site conceptual
models, or alternative designs of natural barrier components, may not be distinguishable if
their effects on dose estimates are small compare with the wider variations that reflect the
uncertainties in performance of the total disposal system over these very long time periods.
Comment 0167-1 makes the analogy between uncertainty increases and the real world
options for setting design requirements for engineered materials and structures such as
bridges. The analogy is not correct in that is confuses two very different situations. For
engineered materials and structures such as bridges, in-service monitoring and maintenance
are assumed to take place and remediate any detected failings. For deep geologic disposal
in contrast, the disposal system is intended to operate passively during the compliance
period, i.e., without the need for human intervention by monitoring or remediation.
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Section 2 Dose Limits
Issue F: The 10,000-year standard
1. The near-term standard requiring DOE to demonstrate that a person living 11 miles away
from the Yucca Mountain site would be exposed to no more than 15 millirem of radiation
per year during the first 10,000 years of repository operations appears reasonable. This
conclusion is based upon the fact that a routine chest x-ray emits 10 millirem, and a
mammogram emits 30 millirem, medical procedures which Lincoln and White Pine County
residents voluntarily undertake. (Comment 0211.1-3)
Response To Issue F:
This comment requires no response.
Section 2 Dose Limits
Issue G: EPA is backpedaling from its previous position on more than 15 mrem/yr
1.	EPA has backpedaled from its previous stance that a 150 millirem is unacceptable. Four
years later, the EPA has ignored its own stated position and instead proposed a standard for
the Yucca Mountain project that's more than twice that. (Comments 0103-6, 0127-2, and
0145-6)
2.	NAS noted that a "general consensus exists among national and international bodies on a
framework for protecting public health," placing a limit of 100 millirems per year on
continuous or frequent exposures from all anthropogenic non-medical radiation sources. Id.
at 4. Following this apportionment principle, this consensus would assign to high-level
waste disposal only 10 to 30 millirem per year. Id. at 4. (Comment 0226-2)
3.	In its June 2001 Response to Comments document addressing its previous iteration of
Part 197, EPA thoroughly rejected a suggestion that it should consider gradually relaxing
its Yucca Mountain radiation standard over the progression of time. The commenter
making this suggestion had proposed allowing the 15 millirem/year standard to increase to
150 millirem/year from 10,000 to 100,000 years, and to 1.5 rem/year from 100,000 to 1
million years. EPA rejected this proposal as "flawed," offering the observation that "[n]o
regulatory body that we are aware of considers doses of 150 mrem to be acceptable, much
less 1.5 rem, for members of the general public." Responses to Comments at 3-8.
In its previous Yucca rulemaking, EPA vigorously defended 15 millirem/year as the
appropriate public health and safety standard, rejecting additional suggestions that the
standard could be relaxed to 70 millirem/year or even 25 millirem/year. EPA emphasized
that "EnPA instructed us to write standards 'based upon and consistent with' the findings
of NAS. The annual risk basis of the 15 mrem limit.. .is within the range of annual risk
levels which NAS suggested." Responses to Comments at 4-5 (citing NAS Report at 5). A
key part of EPA's rationale was therefore to conform its standards to risk levels suggested
by NAS, corresponding to a range between 2 and 20 millirem/year. In its final rule, EPA
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observed that its adoption of the 15 millirem/year standard was based in part on the NAS
Report, noting also that "[t]his level is 15% of the ICRP- recommended total dose limit. It
falls within the range of standards used in other counties and the range recommended by
NAS, and is also consistent with the individual-protection requirement in 40 CFR part
191." 66 Fed. Reg. at 32088 (June 13, 2001).
In its defense of the 15 millirem/year standard, EPA disagreed "particularly
strongly" with a commenter who recommended a 70 millirem/year standard as "adequately
protective," noting that the risk level associated with that standard "is about five times as
high as the risk level associated with the individual protection limit. This is well above the
NAS recommended level and unprecedented in the current regulations of this and other
nations for this activity." Responses to Comment at 4-5, 6. EPA noted that a 70
millirem/year standard would result in "a risk level at Yucca Mountain that is significantly
higher than any facility that falls under 40 CFR part 191, such as WIPP and future
radioactive waste disposal facilities"; and would violate well-established norms of
apportionment, because "70 mrem from one source is too high a proportion of the annual
100 millirem recommended by NCRP and ICRP (excluding background, occupational,
accidental, and medical sources)." Id. at 4-5. On similar grounds, EPA even rejected
several suggestions for a 25 millirem/year standard, concluding that even that level would
be "higher than that recommended by the NAS." Id.
The proposed rule fails entirely to support EPA's dramatic retreat from the
consensus position of NAS and other regulatory and advisory bodies, including EPA's
express rejection of a similar two-tier standard. EPA concedes that it earlier "rejected
similar approaches" to that it now proposes, and expressly rejected a 150 millirem/year
standard as one that "no regulatory body we are aware of' considered acceptable. 70 Fed.
Reg. at 49031. Absent from EPA's new discussion is any reason to believe regulatory
bodies would now consider that standard, much less one more than twice as lenient,
acceptable for the general public. Instead, EPA's rationalizations seem to underscore the
arbitrary and legally dubious nature of the new proposed rule. Most notably, EPA does not
explain how its previous conclusion that such levels were inconsistent with the NAS's
recommendations can now be dramatically reversed. (Comment 0226-4)
4. The unacceptable health risks posed by EPA's proposed 350 millirem/year (1000
millirem/year mean equivalent) standard should not be surprising, for a 350 millirem
standard is higher than anything EPA, or any other regulatory body, ever has approved
before. The NAS report recognized an existing international consensus supporting
substantially more stringent protections. See NAS Report at 41. NAS recommended a
starting point for EPA's rulemaking consistent with that international consensus. As EPA
itself has acknowledged, that would produce a standard in the range of 2-20 millirem/year,
far lower than the standard EPA now proposes.
In its prior rulemaking, EPA recognized that deviating from this international
consensus and from this NAS recommendation would be inappropriate, and rejected as
unsafe proposals to set standards well below the 350-millirem standard it now proposes.
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Those past conclusions indicate that EPA has consistently viewed proposed
standards much lower than the one it now proposes as unprotective of public health,
internationally unprecedented, and beyond the limit of responsible regulation. This also
applies to the EPA's proposal to adopt a two-tiered approach to the human intrusion
performance assessment. (Comment 0226-6)
5.	EPA's Colorado rationale is flatly inconsistent with EPA's past standards and
conclusions, and with the NAS's recommendations. Although EPA has been regulating
anthropogenic radiation exposures for decades, it has never used this type of standard or
invoked this natural background rationale before. Instead, its consistent past practice has
been to follow the international consensus and allow a maximum of 100 millirem/year of
anthropogenic exposures from all sources combined, and to allow individual sources to
contribute no more than 15 millirem/year of exposure, a level it noted was consistent with
the NAS's recommendations (a range of 2 to 20), and that EPA continues to assert is
appropriate for Yucca Mountain in the pre-10,000-year period. 66 FR 32088 (15
millirem/year is "within the NAS-recommended range"); see NAS Report at 41 (describing
the international consensus supporting this level). EPA has viewed the 15 millirem/year
level of protection as consistent with the specific recommendations of the NAS report.
In soundly rejecting suggested 25 millirem, 70 millirem, and 150 millirem
standards, EPA never hinted that existing natural background levels in other places
somehow would have made those higher levels appropriate. See EPA Response to 46
Comments at 4-5 to 4-6. Instead, EPA has taken the consistent position that 15 millirem is
the reasonable limit on anthropogenic exposure from one source. Likewise, where the NAS
spoke of natural background as a benchmark for acceptable exposures, it referred only to
the "concept of negligible incremental dose (above background levels)," a concept that
suggests that repositories should cause negligible incremental changes—not a doubling—of
existing background levels. See NAS Report at 8-9 (parentheses in original). (Comment
0226-49)
6.	EPA has for decades declared radiation doses above 15 to 25 millirems per person per
year to be inadequate to protect public health. EPA has also gone on record that doses
above 100 millirems per year produce unacceptable levels of risk. We urge EPA not to
abandon this position that exposures from all nonmedical man-made sources be limited to
100 millirems per person per year. (Comments 0293-9 and 0302-2)
7.	The proposed rule is EPA's attempt to comply - or get around - the court's order. EPA
proposes a protective standard of 15 millirem/year for the first 10,000 years, and then a
dose limit 23 times higher for the remainder of a million years. This 350 millirem/year
proposal is a higher permissible dose than EPA has ever said is acceptable from radiation to
the public from nuclear activities; higher than any international body indicates is acceptable
for a public dose from planned exposures; and grossly outside EPA's historical risk range.
(Comment 0296-1)
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8.	NAS made clear that the consensus among national and international bodies was there is
a limit of 100 mrem/yr effective dose for continuous or frequent exposures from all man-
made sources other than medical. To suggest that 350 mrem/yr is based upon or consistent
with the NAS recommendations is absurd. (Comment 0311.1-6)
9.	Over the last 30 years, EPA has repeatedly lowered the allowable radiation dose to the
public. The administrative record is replete with EPA's own statements of what constitutes
a protective standard, repeatedly rejecting 150 mrem/yr, and even 70 mrem/yr for the
standard (EPA response to Comments, 40 CFR 197, at 3-8 (2001). (Comment 0311.1-7)
10.	In describing the implications of its conclusions and the common elements with 40
CFR 191, NAS noted that "EPA has endorsed the dose limit and dose-apportionment
recommendations of the ICRP. We endorse this approach." (Comment 0311.1-8)
11.	In the past, the EPA has been extremely specific about what it believes to be the level
of risk from exposure to anthropogenic radiation that is acceptable today. In an April 1997
statement on the Nuclear Regulatory Commission's standard governing licensing
termination which set a 25 millirem per year dose limit with the potential for exposures to
go up to 100 millirem per year under certain conditions, Ramona Trovato, the Director of
the EPA's Office of Radiation and Indoor Air, concluded that "a cancer risk of 1 in 250"
would be "simply unacceptably high." (Comment 0314.1-10)
12.	An August 1997 memorandum from Stephen D. Luftig, the Director of EPA's Office of
Emergency and Remedial Response, and Larry Weinstock, the Acting Director of the
EPA's Office of Radiation and Indoor Air, reiterated these conclusions and included an
analysis which stated that the 25 to 100 mrem per year dose limit proposed by the
NRC was considered to "present risks that are higher than levels EPA has found to be
protective for carcinogens in general and for radiation, in particular, in other others
contexts." In setting previous regulatory standards, the EPA has repeatedly taken the
position that a lifetime incremental risk greater than 1 in 10,000 would be unacceptable.
This level of "acceptable" risk has been codified in the National Emission Standards for
Hazardous Air Pollutants, the National Primary Drinking Water Standards, and the
guidelines for cleanup of sites under the Comprehensive Environmental Response,
Compensation, and Liability Act. In addition, the draft federal radiation protection
guidance proposed by the EPA on December 24, 1994 also specified a goal of limiting the
lifetime risk from exposure to cancer to less than 1 in 10,000. Finally, this level of
"acceptable" risk is implicit in the use of the 15 millirem per year dose limit for Yucca
Mountain during the first 10,000 years. (Comment 0314.1-11)
13.	What is most disconcerting to the City is that EPA has previously rejected a radiation
standard less than the level proposed for Yucca Mountain based on public health grounds.
In its June 2001 Response to Comments document addressing its previous iteration of Part
197, EPA rejected gradually relaxing the Yucca Mountain standard over time. EPA stated
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that "no regulatory body that we are aware of considers doses of 150 mrem to be
acceptable, much less 1.5 rem, for members of the general public." Additionally, in its
previous Yucca rulemaking, EPA defended 15 millirem per year as the appropriate public
health and safety standard, rejecting additional suggestions that the standard could be
relaxed to 70 millirem per year or even 25 millirem per year. EPA's consistent past practice
has been to follow international consensus and allow a maximum of 100 millirem per year
of anthropogenic exposures from all sources combined, and to allow individual sources to
contribute no more than 15 millirem per year. (Comment 0341-3)
14.	These proposed standards clearly contradict the EPA's own assessment that radiation
doses of 100 mrem/yr produce unacceptable levels of risk. (Comment 0349-4)
15.	We do think that there would be under the proposed standards gross violations of
scientific, ethical, and public health principles that consistently have characterized much of
the conduct around proposals for Yucca Mountain. ... We do believe that it doesn't meet
minimal public health and safety requirements. Now proposing a 350 millirem per year
exposure limit, .... is truly vastly outside what even your current rules say is acceptable. ...
a dose of 350 millirem per year does lead to a cancer risk of approximately one in 36,
vastly outside the risk limits that we've been talking about together over the years of one in
10,000 to one in a million. (Comments 0368.2-1, 0368.9-4, and 0368.13-7)
16.	EPA itself has for decades declared any radiation dose above 15 to 25 millirems per
year to be inadequate to protect the public health. ... gone on record that doses of 100
millirems per year produce unacceptable levels of risk. In its own final rule for the first
Yucca Mountain radiation standard, EPA wrote in its response to a comment opposing 70
millirems per year standard, quote, "The risk level associated with 70 millirems is about
five times as high as the risk level associated with the individual protection limit." This is
well above the NAS recommended level and unprecedented in the current regulations of
this and other nations for this activity. (Comment 0368.6-9)
Response to Issue G:
A number of commenters questioned how we could propose to establish limits higher than
those we had previously considered inappropriate or outside the Agency's risk range.
Commenters 0226, 0311.1, 0341, and 0368.6 note that we rejected suggestions that we
establish dose levels above 15 mrem/yr in our 2001 rulemaking. We did so in two
instances. First, we rejected such suggestions regarding the 10,000-year standard, where
we are retaining the 15 mrem/yr dose level. We believe this represents the appropriate
level of protection for the initial 10,000-year period. In the second instance, we rejected
suggestions that we should establish higher dose levels for the period beyond 10,000 years.
We did so primarily because we believed it would be inappropriate to set a numeric
compliance limit for times up to 1 million years, given the uncertainties involved at this
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extended time frame. We chose instead to require longer-term projections, but not to
compare them to a specific compliance limit. NRC would then have flexibility to consider
those projections in its licensing decision to the extent it deemed appropriate. In rejecting
this suggestion, as the commenters note and we acknowledged in our proposal (70 FR
49031, Docket No. EPA-HQ-OAR-2005-0083-0001), we stated that "no regulatory body
that we are aware of considers doses of 150 mrem to be acceptable." However, we also
stated that "the uncertainties involved in very long-term assessments would make it more
difficult to judge compliance with any numerical standard" (70 FR 49031-49032) and that
"[sjetting a strict numerical standard at a level of risk acceptable today for the period of
geologic stability would ignore this cumulative uncertainty and the extreme difficulty of
using highly uncertain assessment results to determine compliance with that standard" (66
FR 32098, Docket No. EPA-HQ-OAR-2005-0083-0042). We did not attempt to project
what that peak dose standard would have been, or the basis for its selection, had we chosen
to establish one. In view of the language in the D.C. Circuit's decision and the weight
accorded by the Court's decision to the committee's technical recommendations
concerning the period of geologic stability, we are now in the position of establishing a
peak dose limit applicable for the period of geologic stability. After considering factors
related to the ability to project or control incremental doses at such long times and the role
of our standards in the NRC licensing process, we proposed 3.5 mSv/yr (350 mrem/yr) as a
level that would appropriately address those factors and "accommodate" our policy
concerns. After considering substantive public comments opposing that proposed level,
however, we are establishing an individual-protection standard of 1 mSv/yr (100 mrem/yr)
to apply for the period beyond 10,000 years. This level is consistent with the overall public
dose limit recommended and accepted by international organizations such as ICRP, IAEA,
and NEA, as well as in the United States by NRC, DOE, and NCRP.3 Adoption and
acceptance by these organizations and entities of the 100 mrem/yr level as protective
provides a clear basis for our determination that this standard will protect public health and
safety in the far future.
Following the recommendation of the NAS, and extending the compliance period to 1
million years, a regulatory time frame unprecedented in this country, prompted us to
3 Although it had used the concept of public dose limits previously, ICRP first described its recommendations
for a comprehensive system of radiation protection in Publication 60 (" 1990 Recommendations of the
ICRP"). ICRP considered two referents in recommending a public dose limit: health detriment and "variation
in the existing level of dose from natural sources." ICRP concluded that estimates of health detriment
"suggest a value of the annual dose limit not much above 1 mSv." Similarly, "[e]xcluding the very variable
exposures to radon, the annual effective dose from natural sources is about 1 mSv, with values at high
altitudes above sea level and in some geological areas of at least twice this. On the basis of all these
considerations, the Commission recommends an annual limit on effective dose of 1 mSv." (Docket No. EPA-
HQ-OAR-2005-0083-0421, Paragraphs 190-191) ICRP re-affirmed this position in its most recent
recommendations: "For public exposure in planned exposure situations, the Commission continues to
recommend that the limit should be expressed as an effective dose of 1 mSv in a year." (Publication 103,
Docket No. EPA-HQ-OAR-2005-0083-0423, Paragraph 245)
This recommendation was adopted in the 1996 International Basic Safety Standards for Protection Against
Ionizing Radiation and for the Safety of Radiation Sources, which was jointly sponsored by IAEA, NEA, the
Food and Agriculture Organization of the United Nations, the International Labor Organization, the Pan
American Health Organization, and the World Health Organization. (IAEA Safety Series 115, Schedule II,
Docket No. EPA-HQ-OAR-2005-0083-0409)
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contemplate the nature of public health protection over such times. As discussed in Issue B
of this section and the preamble to the final rule, we do not believe it is appropriate to view
a standard applicable for as long as 1 million years from within the Agency's traditional
risk-management framework, and would not view a projected dose of 100 mrem/yr in the
far future, with all the attendant uncertainties, as comparable to a 100 mrem/yr dose
incurred today, or even projected to occur within 10,000 years. We conclude that it is
appropriate to approach the post-10,000-year peak dose standard from a broader
perspective of protectiveness. We proposed in the NPRM that the variation in background
radiation across the U.S. could provide a basis for evaluating the significance of releases
from the Yucca Mountain disposal system. We are not, however, using background
radiation as the basis for our final long-term standard. We are instead adopting a level
consistent with the widely-recommended overall public dose limit, which NRC applies to
individual licensed operations today (10 CFR 20.1301).4
Commenters 0226, 0293, 0302, 0311.1, 0349, and 0368.6 raised the issue of
apportionment, an approach in which individual sources or practices are regulated such that
exposure to multiple sources or practices will not exceed an overall dose limit, which ICRP
recommends be set at 100 mrem/yr. The commenters again questioned how we could
propose a standard higher than 100 mrem/yr when we have in the past endorsed the
apportionment approach. As with the range of risks suggested by NAS as a "starting point"
for EPA's consideration, the standards we have established and successfully implemented
for periods of 10,000 years are consistent with the apportionment approach. However, we
do not believe it is either required or reasonable to apply the traditional approach to
apportionment, which we have viewed as consistent with the risk-based standard we are
applying for the initial 10,000-year period, over very long time frames, nor do we agree
that NAS recommended an apportionment approach be applied in determining the peak
dose standard (see also Section 24, Issue B of this document). NAS discussed the concept
and concluded that it had been widely adopted (NAS Report pp. 40-41). However, NAS
also noted that "guidance to date has been for expected exposures from routine practices.
There is little guidance on potential exposures in the far distant future." (NAS Report p.
41) NAS made no specific recommendation that EPA apply the concept to Yucca
Mountain, let alone how the concept should be applied.
We noted in our proposal that ICRP itself took a similar view in its Publication 81,
"Radiation Protection Recommendations as Applied to the Disposal of Long-Lived Solid
Radioactive Waste," stating that "as the time frame increases, some allowance should be
made for assessed dose or risk exceeding the dose or risk constraint. This must not be
misinterpreted as a reduction in the protection of future generations and, hence, a
contradiction with the principle of equity of protection, but rather as an adequate
4
Although this issue is no longer relevant, we do note, however, that the 100 mrem/yr level also reasonably
comports with an analysis of background radiation as well; even when radon doses are estimated using a
more conservative conversion factor suggested by some commenters, 100 mrem/yr is at the low end of
overall background radiation estimates in Amargosa Valley and nationally, and is within the difference
between average estimates for counties in the State of Nevada. (Docket No. EPA-HQ-OAR-2005-0083-
0387) See Section 3 of this document for more discussion of background radiation.
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consideration of the uncertainties associated with the calculated results" (Docket No. EPA-
HQ-OAR-2005-0083-0087).5 We view statements such as this as providing the additional
guidance on interpreting long-term projected exposures that NAS found lacking. If we
wish to acknowledge that "some allowance should be made" in this regard, "adequate
consideration of the uncertainties associated with the calculated results" must be
incorporated into the peak dose limit we select (see Section 6 of this document for
discussion of uncertainty). Selecting 100 mrem/yr as the long-term dose standard strikes a
middle ground between modifying the apportionment approach (e.g., with a somewhat
higher dose constraint with the goal of maintaining total doses close to 100 mrem/yr) and
rejecting it altogether. By doing so, we accept 100 mrem/yr as a standard that protects
public health and safety and maintains a connection to ICRP's recommended system of
radiological protection. Maintaining the 10,000-year standard at 15 mrem/yr is consistent
with the long-held international view of 10,000 years generally as a demarcation point prior
to which projections can be reasonably well-managed and apportionment applied, but
beyond which projections become progressively more uncertain. Our final standards are
protective of public health, meaningful, implementable, and provide for a reasonable test of
the disposal system that is consistent with the NAS Report, D.C. Circuit decision, and the
principles of reasonable expectation.
Moreover, we note that under 10 CFR 20.1301, NRC requires that licensees conduct
operations so that the total effective dose equivalent to individual members of the public
from "the licensed operation" does not exceed 100 mrem/yr. Thus, this regulatory limit
applies to individual licensees operating today, without reference to other potential sources
of exposure to the public. Of course, some types of NRC licensees, such as fuel cycle
facilities subject to our standards in 40 CFR part 190, must meet dose constraints lower
than the 100 mrem/yr limit. Nonetheless, 100 mrem/yr is the public dose limit from
licensed operations imposed in NRC regulations. Readers may object that all licensees are
required to keep public doses As Low As Reasonably Achievable (ALARA), which
provides another check on exposures. However, recognizing the uncertainties inherent in
projecting disposal system performance over hundreds of thousands of years, and
understanding the nature of the licensing process, it is reasonable to anticipate that DOE
would make every effort to ensure its projected doses were as low as possible even without
such a requirement. For this reason, NAS saw no reason to support an ALARA provision,
equating it with "sound engineering practice." (NAS Report p. 125) Consistent with the
NAS position, we have not included an ALARA requirement in our rule.
5 Similarly, IAEA states, in discussing the application of an apportionment approach ("Safety Requirements
for Geological Disposal of Radioactive Waste" (WS-R-4)): "It is recognized that radiation doses to
individuals in the future can only be estimated and that the uncertainties associated with these estimates will
increase for times farther into the future. Care needs to be exercised in using the criteria beyond the time
when the uncertainties become so large that the criteria may no longer serve as a reasonable basis for
decision making'' (Paragraph 2.12, emphasis added) Thus, IAEA recognizes in this consensus document the
general agreement of the geologic disposal community that, while apportionment does apply to geologic
disposal, it cannot be assumed to apply indefinitely. Moreover, IAEA reaches this conclusion on the basis of
uncertainty in projecting exposure from a specific long-term source, without regard to the presumed
knowledge, or lack thereof, of other potential sources of exposure.
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Finally, as we discussed in our proposal, given our statutory responsibility to establish a
site-specific standard, we believe that allocation of 100 mrem/yr to a single source at the
time of peak dose in the far future is reasonable, as other contributors in the Yucca
Mountain area are negligible by comparison (FEIS, DOE/EIS-0250, Section 8.3.2, Docket
No. EPA-HQ-OAR-2005-0083-0086). By relying on current conditions, as recommended
by NAS, rather than speculating on future sources of exposure to the local population, it is
reasonable for EPA to allocate the entire 100 mrem/yr to the Yucca Mountain disposal
system. By assuming that current conditions will apply in the future, we are applying an
approach routinely applied internationally, as well as by EPA in its WIPP compliance
criteria (the "future states" assumption at 40 CFR 194.25).6
As Commenter 0226 notes, we referred in our 2001 rulemaking to the NAS starting risk
range as "recommendations." Because the "starting range" suggested by NAS was fully
consistent with the dose limits and time frames in 40 CFR part 191, as well as with the time
frames of the other regulatory precedents identified by NAS for EPA to consider, we saw
no reason to view NAS as anything other than supportive of the 15 mrem/yr level for the
initial period after disposal. (NAS Report p. 49) We therefore considered our previous
decisions on this point as providing consistency with the NAS position for the time periods
over which both could be said to apply, a fundamental legal requirement under the EnPA.
From that perspective, our narrow view of the NAS suggested "starting range" did not
acknowledge the broader discussion of the range of risks represented by the domestic and
international regulations identified by NAS for EPA to consider, "all of which are
consistent with recommendations from authoritative radiation protection bodies," and
which included the ICRP-recommended public dose limit of 100 mrem/yr. (NAS Report p.
49 and Tables 2-3 and 2-4) However, NAS did not offer recommendations on the final
peak dose limit, or suggest a range of risks that it believed to be scientifically justifiable for
the final standard, leaving the final decision as a policy choice. Instead, NAS explicitly
declined to recommend a level of protection, recognizing that this was a matter best left to
EPA to establish through rulemaking: "We have not recommended what levels of risk are
acceptable.. .The specific level of acceptable risk cannot be identified by scientific analysis,
but must rather be the result of a societal decision-making process. Because we have no
particular authority or expertise forjudging the outcome of a properly constructed social
decision-making process on acceptable risk, we have not attempted to make
recommendations on this important question." (NAS Report p. 20) Indeed, NAS explicitly
acknowledged "that determining what risk level is acceptable is not ultimately a question of
science but of public policy." (NAS Report p. 5) Further, NAS noted that the final
outcome of the rulemaking might diverge substantially from the starting point suggested by
NAS: "Finally we have identified several instances where science cannot provide all of the
guidance necessary to resolve an issue.. .In these cases, we have tried to suggest positions
that could be used by the responsible agency in formulating a proposed rule. Other starting
6 For example, IAEA notes that in modeling over longer time frames, "The emphasis of assessment should
therefore be changed so that the calculations relating to the near-surface zone and human activity are
simplified by assuming present day communities under present conditions." (TECDOC-767, Docket No.
EPA-HQ-OAR-2005-0083-0044, p. 19) The French Basic Safety Rule III.2.f specifies that "The
characteristics of man will be considered to be constant (sensitivity to radiation, nature of food, contingency
of life, and general knowledge without assuming scientific progress, particularly in the technical and medical
fields)." (Docket No. EPA-HQ-OAR-2005-0083-0389, Section 3.2)
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positions are possible, and of course the final rule could differ markedly from any of them."
(NAS Report p. 3, emphasis added) We believe NAS understood that dose projections
would effectively become increasingly stylized as the time period covered by the
assessments increased, and that a compliance standard applicable for times approaching 1
million years might be different in some important respects from their recommendations.
For example, NAS acknowledged that "it is obviously impossible to predict in detail either
the nature or the timing of future climate change" (NAS Report p. 77), and the committee's
frequent references to "bounding" and other approaches reflect its concern that effectively
addressing long-term uncertainties would be critical in implementing compliance
assessments over periods of this length, (e.g., NAS Report pp. 9, 19-20, and 79) NAS's
statement that "the final rule could differ markedly from" the "starting point" implicitly
acknowledges that there might be valid reasons for departing from standards we (and
others) had previously established for much shorter time frames. (NAS Report p. 49)
Indeed, NAS noted a similar consideration in reaching its recommendation, stating that
"selecting a time scale for analysis involves weighing how the scientific basis for analysis
changes with time against the timing at which more numerous future health effects are
likely to occur." (NAS Report pp. 30-31) We believe it is reasonable to consider not only
how the scientific basis for the analysis changes, but also the demands of the regulatory
process, in making the policy selection of a long-term peak dose standard applicable for
times as long as 1 million years. Therefore, contrary to the view of Commenter 0311.1, we
believe our consideration of the factors affecting the "feasibility" of compliance
assessments at such times is consistent with the statements of the NAS committee.
Commenter 0226 also suggests that the NAS committee's view of background radiation is
reflected in its discussion of "the concept of negligible incremental dose (above
background levels)." (NAS Report pp. 7-8) The commenter takes this to mean that the
committee believed "that repositories should cause negligible incremental changes - not a
doubling - of existing background levels." We disagree that the concept of "negligible
incremental dose" is relevant to our establishment of an individual peak dose standard, for
two reasons. First, NAS clearly intended this concept to address the potential that a much
wider population outside the critical group (or RMEI) might receive very small doses,
leading to statistically significant health impacts. NAS viewed this as a condition upon
which the individual-protection standard would adequately protect the general public
("provided that policy makers and the public are prepared to accept that very low radiation
doses pose a negligibly small risk." (NAS Report pp. 7-8). Second, the level of
"negligible" dose (or risk) represented a level "that can, for radiation protection purposes,
be dismissed from consideration." (NAS Report p. 59) Thus, far from an expression
regarding the level of radiation exposures that should be regulated, or how that level should
be derived, NAS was addressing levels that it recognized would be much lower, and
suggesting they should not be regulated. We declined to adopt the NAS position, although
for different reasons we agreed that the individual-protection standard would adequately
protect the general public. See 66 FR 32094-32095.
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Finally, Commenter 0314.1 refers to Agency statements and directives taking the position
that doses of 25 mrem/yr are insufficiently protective. As the commenter notes, these
statements and directives were issued in the context of site cleanups, license termination,
and release of sites for unrestricted use. We do not agree that criteria applicable to
remediation of existing contamination, even if very significant, are comparable to standards
established to assess compliance of a geologic disposal system over hundreds of thousands
of years. See Section 1, Issue C of this document for more discussion of this point. As
noted above, our 10,000-year standards take an approach consistent with the statements and
directives cited by the commenter.
Section 2 Dose Limits
Issue H: Impacts of radiation
1.	EPA's proposal fails to consider the so-called "bystander effect," in which radiation
produces changes in cells that were not directly hit by it but are in the vicin... (Comments
0103-7 and 0145-7)
2.	In fact, Executive Order 13045 that requires federal agencies to specifically address the
potential impact to children's health and safety was summarily ignored. The EPA believes
there exists no disproportionate impact to children. Children are NOT negligible.
(Comments 0130-7 and 0195-8)
3.	Published data that clearly indicates that small amount of radiation can have a significant
impact on the unborn and very young children. Dr. Abram Petkau, head of the Medical
Biophysics Branch of the Canadian Atomic Energy research laboratory in Manitoba,
announced over 30 years ago that chronic low-level nuclear radiation exposure produced
far worse damage to living tissues than high-dose, short-term exposure. He named this the
Petkau Effect. ...
The Petkau Effect seems to cause damage to those cells, which are responsible for
the body's resistance to disease. Swiss engineer and nuclear hazards expert Ralph Graeub
explains in his expose of nuclear radiation hazards, the more drawn-out the radiation (the
Petkau Effect), the lower the total dose required to break the membrane. Small doses of
radiation can be more dangerous than large ones and low-level radiation magnifies all
health risks. Small increases in the continuous radiation such that will be emitted by the
stored high level nuclear waste will not be neutralized and thus cause significant impact to
the very young and the very old, both who have a low immune system. (Comment 0131-2)
4.	A group called The Radiation and Public Health Project (RPHP) (www.radiation.org) is
a nonprofit educational and scientific organization, established by scientists and physicians
dedicated to understanding the relationships between low-level, nuclear radiation and
public health have been measuring the amount of SR-90 released and the impact on young
children. They have collected and continue to collect baby teeth, and using the zip code
have correlated the impact of very low level continuous radiation and the health of the
children.
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DOE with the approval of the EPA is attempting to do something that has never
been done. Beat Mother Nature. EPA must show how the Executive Order 13045 will be
met with the proposed radiation limit in light of the RPHP data. The proposed EPA must
not be adopted until the conflicts are resolved. (Comment 0131-3)
5.	1) By what criteria and through what procedure(s) will the EPA positively determine
that any given manifestation of disease is or is not radiation induced (once Yucca Mountain
is in operation)?
2)	What value constitutes the EPA proposed acceptable death rate per year resulting from
EPA permissible level(s) of radiation emissions by the Yucca Mountain Repository? Is the
much quoted value "one fatality per million per year" EPA generated?
3)	What is the expected rate of onset of radiation-induced disease per year, from which will
flow the EPA acceptable death rate per year?
4)	By what methods does the EPA intend to measure and verify that the actual rate of
disease onset and the actual death rate (resulting from EPA permissible radiation emission
levels) are those that were predicted and deemed acceptable?
5)	What are the anticipated forms of fatal radiation-induced disease in order of prevalence
(by percentage) affecting the doomed individual(s)?
6)	What is the expected average survival time and medical treatment cost of the doomed
individual(s) between positive diagnosis of onset of radiation induced disease and death?
7)	What are the anticipated forms of radiation-induced disease in order of prevalence (by
percentage) among the population of non-fatal cases, within which the doomed
individual(s) form a subset?
8)	What is the expected average medical treatment time and medical treatment cost of those
individuals rendered chronically (but not fatally) ill, as a result of radiation-induced
disease? (Comment 0196-1)
6.	Does E.P.A. know or presupposed if the dosages are "safe" or have the possibility of
being the devastating cause of radiation disease deaths in Nye County? There have been no
NCI reports for six years. (Comment 0198-3)
7.	Is the figure "one person per million"(per year?) chosen to be allowed to die
from radiation exposure correct? Is this the allowable death rate? (Comment 0198-4)
8.	EPA ignore the bystander effect. And it's very clear in the recommendation, they [NAS]
are making a reference to the 10 millirem by standard federal recommendation for research.
(Comment 0209.1-2)
9.	The proposed EPA standard, if ultimately adopted, would allow future residents of
Nevada to suffer 100 times more radiation exposure from releases than levels the federal
government currently permits to residents living near nuclear power plants. (Comment
0209.6-4)
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10.	You have willingly ignored the potential effect that this project could have on children,
women, and the Native-American people we have in our state. We find this to be an unjust
and irresponsible policy. (Comment 0209.13-3)
11.	We blew up [a bomb] at Hiroshima, ... there's a big city right there. ... They're not
dying, they're living, just where the atomic bomb was blowed up at. (Comment 0210.2-1)
12.	Shroeder-Freschette said that 350 mrem/yr causes about three percent of all the fatal
cancers in the U.S. If EPA permitted air polluters to follow such logic, they could save
money and increase profits by claiming victims' health risks were acceptable merely
because they were no worse than those caused by natural events. (Comment 0210.3-5)
13.1 heard you say that the mountain could withstand earthquakes and everything else, but
what if there's a freaky accident, and it happens within? How would we — how would I tell
that I've been exposed? I mean, what are the side effects if I'm exposed? (Comment
0211.2-1)
14.	The EPA website states there is no safe level of exposure to radiation. Radioactive
groundwater contamination from the Yucca Mountain repository is inevitable due to its
siting in a geologically unstable area riddled with hundreds of known earthquake faults.
After the lethal contamination reaches Lake Mead, less than 100 miles away, it eventually
will be carried down the watershed into the Baja California where it will be dispersed into
the Pacific Ocean. How much radioactivity will it take to kill the ocean? We don't know.
How much radioactivity will it take to kill us? The ingestion of minute amounts will do the
trick. (Comment 0211.3-1)
15.	There are over 200 radioactive substances produced in nuclear reactors. Many of them
have exceeding long half-lives. For example, Plutonium-239, one of the most poisonous
substances known to man, has a half-life of 24,000-plus years. It causes genetic damage
that is carried through subsequent generations without additional exposure. Genetic
damage, in practical terms, means that your grandchildren won't look like you, and their
grandchildren won't look human. If there are any. (Comment 0211.3-2)
16.	It appears that the USEPA not fully incorporate findings and conclusions of the
National Academy of Sciences' report on Health Risks from Exposure to Low Levels of
Ionizing Radiation: BEIR VII report (13) into their proposed new EPA radiation standard
for YMP. The ... BEIR VII report identified some additional ways that radiation causes
responses ... in cells; processes which had not yet been recognized at the time of the last
NAS report on this subject (BEIR V). Among these responses are: ... the "bystander
effect", ... and "Genomic instability" ... While EPA used ... the phrase "calculated dose
and or radiation", it is our opinion that instead of using the above phrase there is a need for
experimental data to verify assumption used both by DOE and EPA. (Comment 0214-2)
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17.	It is our opinion that the EPA should have taken a second look at epidemiology studies
at Chernobyl accident and Three Mile Island concerning cancer risk before issuing their
final radiation standard for YMP. .. epidemiological studies using the National Cancer
Registry ... in the Republic of Belarus ... have shown a significant excess of incidence of
cancers of the colon, urinary bladder, and thyroid gland, when compared with a
corresponding adult population of the Vitebsk region. (Comment 0214-4)
18.	However, the EPA should include some additional plain language explanations about
possible radiation exposure and the health risks of the limits set in the proposed rule. This
will help the public put in perspective inaccurate statements by repository opponents about
the so-called "great danger" Yucca Mountain could pose to future generations. (Comment
0217-lb)
19.	The final rule also needs to include perspective on the relative danger to the public
posed 15 and 350 mremlyear levels. EPA should point out that repository worker dose
limits during the preclosure period are set by the NRC at 5,000 mrem/yeav, per 10 CFR Part
63, which NRC believes adequately protects worker health. Even the 350 mremlyear dose
limit is orders of magnitude less than what workers at the repository are allowed to be
exposed to as well as others in the nuclear and medical field. (Comment 0217-7)
20.	EPA's proposed rule is totally lacking any analysis of the health and safety implications
of a 350-millirem (1000-millirem mean equivalent) standard. Such an oversight is not
merely arbitrary and capricious; it represents irresponsible abdication of EPA's
Congressionally defined regulatory role.
Had EPA performed any such analysis, the results would be obvious: the proposed
standard creates a virtually limitless future of unreasonable risks. Nevada's health and
safety consultant has completed the very analysis that EPA has declined to perform, and
concludes (based on accepted correlations between radiation dose and adverse health
effects) that exposure to a 350 millirem additional annual dose over a lifetime would create
a 4.8 percent increase in adult risk of fatal cancer. Furthermore, the radiation dose that
could be received in three to six years would be in the range over which a 40 percent
increase in the cancer rate in children has been directly observed. [See Appendix A.] EPA
offers no rationale explaining why such increases are acceptable. It should come as no
surprise that the President of National Council on Radiation Protection (the premier expert
U.S. body on radiation standards and science) strongly criticized the EPA proposal as
inconsistent with long established national principles of radiation protection at a November
14, 2005 presentation to NRC's ACNW. ...
[Appendix A] provides a summary of the international literature and regulations
concerning dose standards to further support the view that 350 millirem/year constitutes an
unreasonable and dangerous incremental anthropogenic radiation source. [It] concludes
among other things that EPA has selectively and misleadingly quoted from overseas and
international sources in an effort to support its rule, and that the rule would allow an
increase in cancer risk that no other regulatory body considers acceptable, even for
geologic disposal. (Comment 0226-5)
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21.	EPA itself has acknowledged, as has the NAS, the general consensus views that natural
background radiation levels are not "safe." The NAS noted that "[iInternational scientific
bodies currently accept what is called the linear, or no-threshold hypothesis for the dose-
response relationship.... The no-threshold hypothesis holds that there is no dose, no matter
how small, that does not have the potential for causing health effects." In its original 40
C.F.R. Part 197 rule, EPA, after discussing research on the health risks of radiation
exposures, similarly noted that even natural background levels cause human harm. "We
believe," EPA stated, "that the best approach is to assume that the risk of cancer increases
linearly starting at zero dose. In other words, any increase in exposure to ionizing radiation
results in a constant and proportionate risk in the potential for developing cancer." 66 FR
32080-81 (emphasis added). EPA specifically noted that the risk of anthropogenic radiation
could not be considered in isolation, but instead must be considered in addition to the pre-
existing risks created by background conditions. "The risk of interest," EPA stated, "is not
at or near zero dose, but that due to small increments of dose above the pre-existing
background level." Id. at 32080 n.6. It is for this reason that EPA in the past has always
sought to keep anthropogenic exposures at levels well below background levels; it has
respected the scientific consensus that even background levels kill. See also EPA, A
Citizen's guide to Radon, OAR-2005-0083- 0058, at 2 (noting that background levels of
radon kill an estimated 21,000 Americans every year, and that radon is a larger source of
death than drunk driving). (Comment 0226-53)
22.	Executive Order 13045 requires federal agencies to explicitly address the potential
impact to children's health and safety. We see no evidence in this proposed rule that your
agency has addressed this executive order. Does the EPA actually believe that there exists
no disproportionate impact to children? (Comment 0268-4)
23.	Human x-ray radiation accounts for about 79% of man made radiation exposure in the
USA. High LET inhalation exposures due to radon are 52%; high LET for exposures
ingestion is 5%, and cosmic radiation account for 4%. The natural background radioactivity
in human tissue is in effect in equilibrium or steady state with the particular diet and water
concentrations of the nuclide ingested. There is a slight deviation in body content which
changes with age for a given exposure, and this has been recognized for 226Ra and uranium
isotopes. The low-LET directly ionizing photon component of cosmic radiation is 12%;
low-LET radiation from earth exposure is 20%, and Low LET ingestion is 7% as cited in
the BEIR VII report. It is unclear to us what type of radionuclide exposure are
hypothesized in the EPA proposed new radiation standard what is the risk is relative mix of
high or low LET exposures? (Comment 0270-6)
24.	The important YMP health risk is posed by ingestion in contrast to background
radiation where the principle concern is external radiation. Chronic exposure to internal
radiation appears to be important according to Smith and Kemball in 1998. They concluded
that chronic exposure to low activity sources may have the potential to become significant;
this is of particular concern for internal doses of radiation...Finally, the EPA justifies the
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new radiation exposure standards based on the radiation absorbed during routine x-rays. A
typical dental x-ray, for example, results in 10 mRem of exposure and a mammogram
produces 30 mRem. This analogy is misleading due to differences in the manner that one
receives the radiation dose. Exposure to alpha radiation from plutonium in contaminated
drinking water produces exposure to the entire body including bone marrow and other
tissue that is sensitive to radiation damage. (Comment 0270-7)
25.	Given that the reason EPA has to re-formulate this standard, a directive to comply with
National Academy of Science guidance, I strongly recommend that the final standard take
into consideration the BEIR VII observations that 70 year lifetime annual exposure to 350
millirem will lead to cancer in 1 in 40 men, 1 in 30 women, and even more in children. Of
these incidents, half would be fatal. (Comment 0306-11)
26.	Calculations of the 15 picocuries/liter limit for drinking water actually result in 713
millirem per year exposure, if 2 liters of drinking water at maximum "safe" levels are
consumed per day. (Comment 0306-5)
27.	Calculations for a 30 year exposure are very inappropriate. Local immigrant resident
families are multi-generational, and Timbisha Tribal members are also likely to remain at
their one homeland location in Death Valley. (Comment 0306-6)
28.	2 liters of water per day is absurd in this climate. Day-time temperatures can be over
125 degrees for a month or more. The most conservative estimates for daily water
consumption are one gallon per person for an indoor sedentary lifestyle. A ranch worker in
Death Valley drinking 12 liters a day for 70 years has an annual exposure of 4.278 rem at
maximum permitted plutonium levels, and a lifetime exposure of about 300 rem.
(Comment 0306-7)
29.	EPA's and NRC's proposed allowance for 350 millirem per year radiation doses to
people living downstream from the leaking dump - the, equivalent of about 58 full chest x-
rays per year - will cause cancer, birth defects, and other maladies - as verified recently by
the National Academies of Science Biological Effects of Ionizing Radiation (BETR VII)
report — at alarming rates and must be withdrawn. Current standards of 15 millirem per
year from all pathways, and 4 millirem per year from drinking water, must be applied for
the full million year regulatory period. (Comments 0310-2 and 0355-2)
30.	The radiological impacts on children should be explicitly considered in the Department
of Energy's performance assessments in order to ensure that they are not disproportionately
affected by the repository. (Comment 0314.1-8)
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31.	International Commission on Radiological Protection leading to the development of age
specific dose conversion factors for ingestion and inhalation. These dose models were
published between 1989 and 1996 as a series of five ICRP reports that reveled that, for
many radionuclides, children can receive higher doses than adults for the same level of
ingestion or inhalation. These dose models have been adopted by the European Union's
European Basic Safety Standards and the International Atomic Energy Agency's
International Basic Safety Standards.
Following the publication of these ICRP reports, the EPA's 1999 Federal Guidance
Report 13 included a discussion of the heightened cancer risk from radiation with
decreasing age at exposure. The CD supplement to Federal Guidance Report 13 issued by
the EPA in 2002 included an extensive database of both dose and risk coefficients for
ingestion and inhalation showing a heightened risk to children from exposure to many
radionuclides. Finally, the BEIR VII Committee has published the most up to date review
of the available scientific information, and has made specific recommendations regarding
age specific risk coefficients for exposure to low-level radiation. (Comment 0314.1-16)
32.	Incredibly, EPA has claimed that "the Agency does not have reason to believe the
environmental health risks or safety risks addressed by this action present a
disproportionate risk to children." EPA, asks for evidence to the contrary. I would refer
EPA to the work of Alice Stewart and George Kneale for starters (dating back to the
1950s, when Alice Stewart first proved that x-ray doses to the fetus in-utero causes cancer,
leukemia, and other maladies) which shows clearly that children are disproportionately
vulnerable to radiation's harmful impacts to health. Specifically, EPA should review the
following peer-reviewed scientific studies. (Comment 0324-10)
33.	Executive Order 13045 requires federal agencies to explicitly address the potential
impact to children's health and safety. We see no evidence in this proposed rule that your
agency has addressed this executive order. Does the EPA actually believe that there exists
no disproportionate impact to children? (Comment 0328-3)
34.	Without endorsing EPA's suggested repository annual dose limit of 350 mrem, it is
noted that this limit is well below the dose at which physiological impacts to the human
body from radiation can be discerned. Also, the proposed limit is below radiation exposure
levels experienced by many people today, both occupationally and from natural
background radiation. (Comments 0330-2 and 340-6)
35.	The EPA should also review this ICRP Report and incorporate its findings on low dose
impacts in further re-evaluation of exposures to future human populations. Merely offering
token reductions in the permissible annual doses is insufficient. (Comment 0331-2)
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36.	For the 350 mrem/yr CEDE, it has been estimated that one in thirty-six persons so
exposed will develop cancer. Such an exposure, we are told by the industry and its
regulators, is now the "average exposure" experienced by members of the public from
"background" radiation (including indoor radon). EPA must respond to the obvious
question: what would be the total exposure from all radiation sources in the future for those
who would also receive the maximum dose from the disposal facility plus "background"
and doses from any of many other sources? What would be the biologic toll on recipients?
(Comment 0331-5)
37.	In the initial discussion of the "Reasonably Maximally Exposed Individual" (RMEI),
EPA identifies this individual as an adult presumably male individual - the "Standard (or
Reference) Man," who would be the equivalent of the nuclear industry worker of existing
public dose standards. The persons for whom the exposure standard should be set are
members of the public who are embryo, fetus, rapidly growing young child, pregnant
woman and her ova, the elderly, and those with previously impaired health. All health and
genetic impacts now associated with radiation exposures — not only cancers and their risks
— must be included in the dose calculations. (Comment 0331-7)
38.	In Section 197.2, Appendix A The values assigned for "radiation incident on the body
or, for internal sources, emitted from the source" may have been generalized from available
information, but they may not accurately represent the internal organ doses that are
received by recipients other than the "reasonably maximally exposed individual" resident
farmer (or other) — who represents "standard man". The W R value for alpha particles
remains at 20, despite research indicating that it is or may be substantially higher. A most
conservative value would better provide a margin for error in our present beliefs of the
hazard. The use of generalized weighting factors for organ doses fails to address the
potential adverse impacts on actual dose recipients. (Comment 0331-9)
39.	Not only would these horrifically lack standards cause cancer, but they would
drastically increase birth defects, genetic damage, and other maladies. (Comment 0349-1)
40.	The proposed level of protection at the time of peak dose is consistent with position
statements of... [t]he Health Physics Society [which] has noted that there is substantial and
convincing scientific evidence of health risks following high-dose exposures. However, the
Society notes that below 5 to 10 rem (which includes occupational and environmental
exposures), risks of health effects are either too small to be observed or are nonexistent.
The Society.. .recommends against quantitative estimation of health risks below an
individual dose of 5 rem/yr, or a lifetime dose of 10 rem (equivalent to an average annual
dose of about 125 mrem) above that received from natural sources. The Society further
notes that estimation of health risk associated with radiation doses that are of similar
magnitude as those received from natural sources should be strictly qualitative and
encompass a range of hypothetical health outcomes, including the possibility of no adverse
health effects at such low levels. (Comment 0352-21)
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41.	It starts with the false idea that since too much radiation is harmful, some or any
radiation is harmful. This is simply not how it works. There is evidence that areas with
higher background radiation have better health, surprising as that seems. In any case, the
amount of radiation exposure added by SNF shipments and storage is to small to make any
difference, positive or negative. (Comment 0356.1-3)
42.	If workers can face up to 500 millirems/year why is the public limit 350/year? (What is
the threshold of negative health effects?) (Comment 0367.1-2)
43.	Why aren't the recommendations of the Bier Report incorporated into the Standards?
(Comment 0367.2-1)
44.	Is EPA considering the effects of different types of radiation? (Comment 0367.2-3)
45.	For the first 10,000 years, people exposed to ... a lifetime cancer rate of one in 835
people. Then it dooms future generations to a new radiation standard of one in 36 cancer
rate	 This is a complete violation of EPA's responsibility to protect public health and
the environment. A standard based on a one in 36 cancer rate is not a standard. It is a
death sentence. This proposal to allow 350 millirem per year radiation doses to people
living downstream ... would cause cancers, birth defects, and genetic damage. (Comments
0368.1-3 and 0368.12-3)
46.1 think there's been a consistent and deliberate attempt to downplay the effect of
radiation on human health. (Comment 0368.15-1)
Response to Issue H:
Many of the commenters in this section have made reference to the risk estimates that EPA
uses for assessing the impacts of radiation exposure. The comments were generally
phrased in relation to the proposed peak dose standard of 3.5 mSv/yr (350 mrem/yr). We
are not establishing the proposed 350 mrem/yr level as our final peak dose standard;
instead, we are establishing 1 mSv/yr (100 mrem/yr) as the standard to apply for the period
beyond 10,000 years and up to 1 million years. Because the comments addressed
fundamental issues involved in estimating risks from radiation exposure, however, we are
responding to the comments on this topic.
Using a conversion factor of 5.75 x 10"7 fatal cancers per mrem, our final peak dose
standard of 1 mSv/yr (100 mrem/yr) represents a nominal annual risk of fatal cancer of
5.75 x 10"5, or 5.75 in 100,000 (we note thatNAS applied a smaller conversion factor of 5
x 10"7 fatal cancers per mrem). This is comparable to the range of risks represented by
domestic and international regulations that NAS suggested EPA consider, and which NAS
stated were "consistent with recommendations from authoritative radiation protection
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bodies" (Comments 0196-1 and 0198-4 appear to refer to the low end of the NAS starting
range in their references to "one in a million per year"). (NAS Report p. 49 and Tables 2-3
and 2-4) EPA does not consider this level of risk to be excessive in the context of a
standard applicable for the period from 10,000 years to 1 million years, given the increased
uncertainty in dose projections and the questionable assumption that current risk estimates
can be applied to the extreme far future. Risk correlations for any time frame (even the
present) cannot be considered absolute and precise, particularly when applied in a
prospective manner to the behavior of a disposal system that will operate passively for
hundreds of thousands of years. When time frames on the order of 1 million years are
considered, it is reasonable to view the nominal risk associated with the 100 mrem/yr peak
dose standard as a reasonable level of risk. We are focusing discussion of the risk
associated with the peak dose standard on annual risk, as this was the metric considered
appropriate by the NAS committee, although it did not recommend a particular risk level.
The Agency has determined that this standard will protect public health and safety.
Comments 0103-7, 0145-7, 0209.1-2, and 0214-2 (in part) refer to the bystander effect and
ask why EPA did not consider it in setting the Yucca Mountain post-10,000 year standard.
The bystander effect is one of the key areas of low dose effects research being funded by
DOE and others around the world. ("Health Risks from Exposure to Low Levels of
Ionizing Radiation" (BEIR VII), Docket No. EPA-HQ-OAR-2005-0083-0430, p. 314) It
refers to experimental observations that cells in the vicinity of a cell hit by radiation show
responses similar to the directly damaged cell. There are two reasons why we did not
consider the bystander effect in this rulemaking. First, the experimental results are not
always consistent and the biological mechanism behind the response is still being debated.
Some experiments show a net beneficial impact and others an increased detriment. Also,
most of the experiments are conducted in vitro and may not be reproducible in vivo.
Therefore, we must conclude that the science is not mature enough to have an impact on
our regulation. The second reason is that we rely on over 100 years of direct observations
of the harmful effects of radiation on humans. Chief among the studies we rely on is the
Life Span Study of the survivors of the atomic bombs in Hiroshima and Nagasaki, Japan.
These epidemiological studies remain the best evidence we have for quantifying the
apparently linear dose response of excess cancers resulting from radiation exposure. (BEIR
VII, Docket No. EPA-HQ-OAR-2005-0083-0430, Chapter 6)
Comments 0130-7, 0131-2, 0131-3, 0195-8, 0209.13-3, 0268-4, 0306-11, 0314.1-8,
0314.1-16, 0324-2, 0324-10, 0328-3, and 0331-7 assert that EPA has not properly
accounted for the disproportionate risk to children from exposure to ionizing radiation.
Many of these comments claim that we have ignored Executive Order 13045, Protection of
Children From Environmental Health Risks and Safety Risks (62 FR 19883-19888, April
23, 1997). In fact, the risk to children is explicitly accounted for in EPA's radionuclide
cancer risk coefficients (Federal Guidance Report 13, EPA-HQ-OAR-2005-0083-0072).
EPA's standards, whether risk-based or dose-based, are designed to be protective over a
lifetime of exposure. Lifetime dose or risk is obtained by adding an individual's age-
specific dose or risk for each year of exposure. Therefore, the somewhat higher risks per
unit dose to infants and children are greatly offset by their receiving most of their total
lifetime dose as adults.
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Comment 0131-2 refers to the Petkau Effect in stating that chronic exposure at low levels
of radiation can be more harmful than high doses, and that there is increased harm to
fetuses, very young children, and the elderly from chronic exposure. Since the
observations referred to as the Petkau Effect are from in vitro observations following a
radiation dose of 700 millirads delivered over about 12 hours, they are not relevant at the
level of the individual-protection standard (for low-Linear Energy Transfer (LET)
radiation, the radiation weighting factor is 1, so 1 millirad is equivalent to 1 millirem - see
the response to Comment 0331-9 below) Our standard would equate to a dose rate several
thousand times smaller than that required for the alleged effect. (Docket No. EPA-HQ-
OAR-2005-0083-0415) Nevertheless, EPA agrees that infants and children are at higher
risk from radiation and that is why our standard is designed to be protective for all ages
over a lifetime of exposure. Variations in risk at each age are accounted for in our risk
model.
Comment 0131-3 refers to the studies of strontium-90 (Sr-90) in teeth conducted by the
Radiation and Public Health Project (RPHP). The commenter suggests that the risks to
children are higher than EPA's current estimates. EPA has examined the RPHP data and
found serious flaws in the epidemiological methods used. For example, NRC reports on
radionuclide releases from nuclear power plants consistently show that Sr-90 releases are
far too low to account for the trend reported by RPHP (EPA-HQ-OAR-2005-0083-0381,
EPA-HQ-OAR-2005-0083-0382). Further, RPHP has not identified the exposure pathway
leading to the claimed increases. The most likely source of Sr-90 in deciduous teeth is
milk. EPA's monitoring data show that Sr-90 levels in milk have been declining since the
cessation of atmospheric nuclear weapons testing ("Historical Summary of Strontium-90 in
Milk Surrounding the New Jersey/New York City Metropolitan Area," Docket No. EPA-
HQ-OAR-2005-0083-0404). No environmental sampling was performed by RPHP to
substantiate claims that Sr-90 concentrations in milk or any other media near nuclear power
plants are different from concentrations in other parts of the country. For these reasons, we
do not believe the studies referenced by the commenter are credible.
Comment 0196-1 asks a series of questions but makes no specific comment regarding the
proposed amendments. The commenter is referred to EPA's cancer risk assessment
methodology as described in Federal Guidance Report No. 13 [Cancer Risk Coefficients
for Environmental Exposure to Radionuclides, EPA 402-R-99-001, Sept. 1999; (Docket
No. EPA-HQ-OAR-2005-0083-0072)] and other relevant reports of the National Research
Council of the National Academies of Science, such as the BEIR VII report, "Health Risks
from Exposure to Low Levels of Ionizing Radiation," The National Academies Press, 2006
(EPA-HQ-OAR-2005-0083-0430), for answers to the risk-related questions asked in this
comment. Questions about future health care delivery in the vicinity of Yucca Mountain
are outside the scope of our standard-setting role.
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Comments 0198-3, 0198-4, and 0209.13-3 refer to the harmful effects of radiation,
question whether EPA has adequate knowledge to quantify these effects, and further
question the acceptability of the risks that EPA has deemed acceptable for various exposure
scenarios. Our estimates of cancer risk from radiation exposure are based on human data,
primarily epidemiological studies of the Japanese atomic bomb survivors and, for radon
risk, studies of underground uranium miners. (For discussion of Japanese survivor studies,
see Chapter 6 of the BEIR VII report, Docket No. EPA-HQ-OAR-2005-0083-0430; for
uranium miner studies, see the BEIR VI Report, "Health Effects of Exposure to Radon,"
Docket No. EPA-HQ-OAR-2005-0083-0426, particularly Appendices D and E) A small,
but statistically significant, increase in excess cancers has been shown in these populations
at cumulative exposures in the range of 5 to 10 rem above background. Estimates of excess
cancer risk are assumed to vary linearly with dose below this observable range. Using this
linear non-threshold (LNT) approach and detailed gender-, organ-, and age-specific data
from these cohorts, we are able to estimate risks that are age and gender specific and
integrate these risks to characterize the risk to an exposed population. Therefore, our risk
estimates for a lifetime of exposure inherently account for variations in risk over a lifetime.
Comment 0209.6-4 states that our proposed peak dose standard of 350 mrem/yr is 100
times higher than the current NRC standard for residents living near nuclear power plants.
This is incorrect — the NRC facility limit is 1 mSv (100 mrem)/yr. For nuclear fuel cycle
facilities, there are also other standards, such as EPA's regulations at 10 CFR part 190, that
must be met. Nevertheless, since our standard beyond 10,000 years is now 1 mSv /yr, the
NRC and EPA standards are comparable.
Comment 0210.2-1 implies that the current-day situation in Hiroshima, Japan, should mean
that there is no risk from Yucca Mountain in the future. There is no similarity between the
residual radioactivity on the ground in present-day Hiroshima and the future activity of the
in situ wastes in Yucca Mountain. The initial activity in Hiroshima was from fission and
activation products which have relatively short half-lives and are now mostly decayed
away. The activity in Yucca Mountain at the time of peak dose will come from the much
longer half-life radionuclides present in the waste.
Comment 0210.3-5 attempts to draw a correlation between our proposed use of variations
in natural background as a metric forjudging Yucca Mountain's performance in the
extreme far future (as detailed in the 2005 proposal) and the approach used for setting air
pollution standards today under the Clean Air Act. The comment is editorial, but we note
that the statutory requirements for setting the peak dose standard at Yucca Mountain are in
the Energy Policy Act of 1992 and are unrelated to the requirements of the Clean Air Act.
Comment 0211.2-1 refers to very low probability events at Yucca Mountain and raises the
question of how the commenter would know he or she has been exposed. We have
explained elsewhere in this document how these low probability events have been dealt
with (see Section 16 of this document). However, in general, the performance standards
for the disposal system during the time to peak dose are set at a level where the receptor is
protected without requiring he or she have any knowledge of the release or take any
subsequent corrective action.
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Comment 0211.3-1 refers to lethal doses of radioactivity in ground water eventually
reaching the ocean. The estimates of peak dose from plausible releases from Yucca
Mountain do not support the scenario raised by this comment. The water that moves below
Yucca Mountain moves south and southeast in a closed basin and therefore, there is no
physical pathway for any contamination to reach Lake Mead or the Pacific Ocean in the
ground water. (See the 2001 BID, Docket No. EPA-HQ-OAR-2005-0083-0050)
Comment 0211.3-2 is a rhetorical statement about genetic risks from radiation exposure.
Based on human epidemiology ["Health Risks from Exposure to Low Levels of Ionizing
Radiation" (BEIR VII), The National Academies Press, 2006 (EPA-HQ-OAR-2005-0083-
0430)], no observable genetic effects would be expected as a result of releases from Yucca
Mountain at the level of our peak dose standard.
Comments 0214-2, 0310-2 and 0367.2-1 state that we did not fully incorporate the findings
and conclusions from the NAS BEIR VII report. In fact, it will take us the next few years
to incorporate the BEIR VII recommendations and make necessary updates to its risk
assessment methodology. However, the overall risk estimates of the BEIR VII Committee
are compatible with EPA's current risk estimates found in Federal Guidance Report No. 13
(FGR 13). [BEIR VII, p. 15 (EPA-HQ-OAR-2005-0083-0430); FGR 13, p. 182 (EPA-HQ-
OAR-2005-0083-0072)] Any changes that result from our incorporation of BEIR VII
would not likely have any impact on the individual protection standard.
Comment 0214-4 encourages us to take into account the results from epidemiological
studies of populations exposed from the Chernobyl accident, particularly Belarus, and from
the accident at Three Mile Island. We do not believe that there is any evidence of
increased cancer incidence from the Three Mile Island accident, from which there were
very low off-site doses. The commenter makes note of increased colon, urinary tract and
thyroid cancers among exposed individuals. Current epidemiology shows a significant and
increasing risk of thyroid cancer among those exposed as children from the Chernobyl
accident. There are anecdotal reports of increases in other cancers among first responders
and other highly exposed cohorts. This data is not yet statistically significant, but we
continue to follow these studies. At present, the Chernobyl data does not indicate a need
for us to make changes to ours risk estimates. See the 2003-2005 report of the Chernobyl
Forum, Docket No. EPA-HQ-OAR-2005-0083-0419.
Comment 217-lb states that we should include some additional plain language
explanations about possible radiation exposure and the health risks of the limits set in the
proposed rule. We believe that the preamble of the final rule adequately presents
understandable information about radiation exposure and risk associated with the standard.
In the preamble, we state that the nominal annual risk of the 100 mrem/yr long-term peak
dose standard is 5.75 x 10"5, which the Agency has determined will protect public health
and safety.
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Comments 0217-7 and 0367.1-2 compare our proposed standards for exposures after
10,000 years with NRC's current standard of 5 rem per year for radiation workers
(although Commenter 0367.1-2 incorrectly states that this limit is 500 mrem/yr) and
suggest that this perspective should be highlighted in the rule. Exposure limits for workers
are always higher than for the public for many reasons, e.g., voluntary vs. involuntary
exposures. Therefore, we believe that this information is not germane to our Yucca
Mountain standards, which apply to the health and safety of the general public, not
workers.
Comment 0226-5 notes that we did not perform a health analysis for the post-10,000 year
proposal. At extreme far future times, such an analysis becomes so uncertain as to be
meaningless. As we discuss in the preamble to the final amendments, the approach that we
have taken relies instead on setting a standard that requires a reasonable expectation that
the period of peak dose in the next 1 million years will not cause the reasonably maximally
exposed individual (RMEI) to receive more than 1 mSv/yr (100 mrem/yr). As discussed in
the preamble, the 100 mrem/yr level is protective of public health and safety and
constitutes a robust standard for public health protection in the far future. (70 FR 49040)
International organizations such as ICRP, IAEA, and NEA recommend its use as an overall
public dose limit in planning for situations where exposures may be reasonably expected to
occur. Domestically, both NRC and DOE adopt the 100 mrem/yr level in their systems of
regulation (10 CFR 20.1301 and DOE Order 5400.5, respectively), and NCRP also
endorses the ICRP system of protection (NCRP Report 116, Docket No. EPA-HQ-OAR-
2005-0083-0407). EPA therefore acknowledges and concurs in the broad consensus in the
protectiveness of the 100 mrem/yr level that makes it especially suitable for application to
the extreme far future, when planning for and projecting public exposures is much less
certain.
This commenter also estimates that the excess lifetime fatal cancer risk from receiving 3.5
mSv per year (the 2005 proposed standard) for life is 4.8%, whereas EPA calculates a risk
that would be close to 1.5 % for this extreme case. The commenter's assertion is also
addressed in Section 5 of this document.
The same commenter (0226-5) quotes from the BEIR VII study a statement that"... studies
of cancer in children following exposure in utero or in early life indicate that radiation-
induced cancers can occur at low doses. For example, the Oxford Survey of Childhood
Cancer found a '40 percent increase in cancer rate among children up to [age] 15.' This
increase was detected at radiation doses in the range 10 to 20 mSv." The commenter then
suggests that the proposed Yucca Mountain standard of 3.5 mSv per year received each
year for 3 to 6 years could achieve doses in this range and result in exposed children having
an excess cancer rate that is 40 percent higher than the baseline risk. The commenter has
misinterpreted the BEIR VII report. The Oxford Survey of Childhood Cancer found the 40
% increase in the cancer rate among individuals who were exposed in utero to doses of 10
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to 20 mSv. In other words, excess cancers were observed up to age 15 that could be
attributed to the in utero dose, not to doses received over a period of years after birth. The
maximum allowed dose that an embryo/fetus could receive under the final Yucca Mountain
standard would occur over a 9-month period and likely be below 1 mSv and thus far below
10 mSv. EPA's current risk estimates take into account age-dependent differences in
sensitivity to radiation. Comment 0270-9 in Section 5 of this document refers to the same
study.
Comment 0226-53 refers to EPA's current position that background levels of exposure
carry some risk of cancer under the Linear No Threshold model of carcinogenesis, an
assertion that EPA supports.
Comments 0270-6, 0270-7, and 0367.2-3 refer to differences in low- and high-Linear
Energy Transfer (LET) radiation and internal and external exposures as a function of the
radionuclides contributing to the projected doses from Yucca Mountain. The commenters
are referred to DOE for projections of which radionuclides are expected to be dominant
contributors to projected doses across time. (DOE Final EIS, Chapter 5, Docket No. EPA-
HQ-OAR-2005-0083-0086). EPA's standards are expressed as committed effective dose
equivalents that explicitly account for differences in low- and high-LET radiation and
internal and external exposure to different organs. Overall correlations between dose and
risk are commonly used in establishing standards for long-term disposal.
Comments 0306-5, 0306-6, and 0306-7 refer to the doses from ground-water ingestion at
the time of peak dose and take issue with EPA's ground-water ingestion pathway default
exposure parameters (i.e., consumption of 2 liters per day). We believe that these
comments are out of the scope of our present rulemaking since they pertain to the details of
the ground-water standards compliance assessment which was not affected by the D.C.
Circuit decision on the challenges to the 2001 standards.
Comments 0306-11 and 0324-2 refer to the risk estimates in the NAS BEIR VII report.
The commenters calculate that the excess cancer incidence risk for 70 years exposure at 3.5
mSv/yr (the 2005 proposed individual protection standard) is 1 in 40 for men and 1 in 30
for women (2.5% and 3% excess risk, respectively). These calculations are slightly higher
than the BEIR VII Committee's estimates of fatal cancer risk using their preferred risk
estimates for low-LET radiation exposure (BEIR VII, Table ES-1, p. 15, EPA-HQ-OAR-
2005-0083-0430). This comment also incorrectly interprets EPA's responsibility as being
to "comply with National Academy of Science guidance." Apparently the commenter is
referring to the ruling of the U.S. Court of Appeals for the District of Columbia Circuit that
on July 9, 2004, remanded the portions of the standard that addressed the compliance
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period (Nuclear Energy Institute v. Environmental Protection Agency, 373 F.3d 1 (D.C.
Cir. 2004). The BEIR "guidance" referred to by the commenter is unrelated to the court
ruling regarding the Yucca Mountain report issued by the National Academy of Sciences in
1995 (Docket No. EPA-HQ-OAR-2005-0083-0076).
Comments 0330-2 and 340-6 are identical and are supportive of EPA's proposed standard,
stating that the proposed standard reflected levels experienced by many people today from
background radiation.
Comment 0331-2 urges EPA to incorporate ICRP's findings on low dose impacts. EPA
does review and, where appropriate, incorporate the scientific data published by ICRP.
Examples of how ICRP reports are used by EPA can be found in the response to Comment
0331-7 below.
Comment 0331-5 states that EPA should consider the total toll on the future RMEI from
background radiation, releases from Yucca Mountain, and other sources. Any estimation
of other sources of exposure are beyond the scope of EPA's statutory authority and this
rulemaking. EPA's dose standard refers to the dose arising from radionuclides released
from the waste emplaced in Yucca Mountain, and does not include the dose from natural
background radiation.
Comment 0331-7 wrongly assumes that the RMEI is based on an adult male. In proposed
Appendix A to 40 CFR Part 197 (70 FR 49064, Docket No. EPA-HQ-OAR-2005-0083-
0001), EPA specifies that effective dose equivalent must be calculated using the tissue
weighting factors from ICRP Publication 60 (ICRP 60) and the methodology for dose
conversion found in ICRP Publication 72 (ICRP 72) (Docket Nos. EPA-HQ-OAR-2005-
0083-0421 and 0427, respectively). The dose conversion factors (DCFs) in ICRP 72 are
age-averaged values that account for age- and gender-specific differences in organ dose
distribution and detriment.
Comment 0331-9 asserts that the radiation and tissue weighting factors used by EPA to
calculate effective dose equivalent may underestimate the true dose, particularly regarding
the Wr for alpha radiation. EPA's use of a Wr for alpha radiation of 20 is consistent with
the recommendations of the ICRP (ICRP 60, p.6) (Docket No. EPA-HQ-OAR-2005-0083-
0421) and the NCRP (NCRP Report 116, p. 20). (Docket No. EPA-HQ-OAR-2005-0083-
0407) EPA believes that the value of 20 currently applied to alpha particles is reasonable.
EPA also uses the tissue-weighting factors recommended by ICRP and NCRP to determine
effective dose equivalent. In contrast to the commenter's assertion, these tissue-weighting
factors may overestimate certain doses. The projected doses from the presumed dominant
radionuclides at the time of peak dose, neptunium-237 (Np-237) and plutonium-242 (Pu-
242) (DOE Final EIS p. 5-29) will lead to an overestimation of the bone surface dose that is
the largest portion of the dose. The reason is that both the ICRP-26 and ICRP-60 tissue-
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weighting factors for bone surface are in reality the tissue-weighting factors for uniform
deposition of a radionuclide in bone. The ICRP acknowledged that the current
methodology overstates the risk to the bone from certain transuranic bone-surface-seeking
radionuclides by a factor of about 5 (Puskin and Nelson, Health Physics, Vol. 63, No. 5, pp.
579-580; with response from ICRP on p. 590; Docket No. EPA-HQ-OAR-2005-0083-
0394). Since dose is a surrogate for risk, it follows that the bone dose portion of the
weighted effective dose equivalent will lead to an overestimation of the effective dose
equivalent for these radionuclides.
Comment 0349-1 refers to the genetic effects and birth defects that would result from the
proposed standard in addition to the excess cancers. These additional endpoints are
accounted for in the tissue weighting factors used to calculate effective dose equivalent.
Comment 0352-21 states the position of the Health Physics Society that risk should not be
quantified below individual doses of 5 rem per year or lifetime doses greater than 10 rem.
The commenter further notes that there is a possibility that there are no adverse health
effects at exposures of 3.5 mSv/yr (350 mrem/yr). While EPA uses the LNT model for
calculating cancer risk at low doses, we also acknowledge that there is a possibility of no
adverse effects. There is, however, insufficient evidence to fully define the dose response
curve at very low doses, so EPA follows the recommendations of the ICRP, NCRP, NAS
and others in assuming that the dose response is linear for all doses above zero.
Comment 0356.1-3 states that the doses from SNF shipments and storage will be too small
to affect the Yucca Mountain dose compliance assessment. Since neither transport nor
storage will be relevant dose pathways at the time of peak dose, this comment is outside the
scope of the rule. The commenter also raises, as an aside, the possibility of a beneficial
(hormetic) effect from the radiation. This possibility is not considered for the same reasons
addressed in the response to Comment 0352-21.
Comments 0368.1-3 and 0368.12-3 refer to the possible health effects from the proposed
3.5 mSv (350 millirems)/yr standard as unacceptable, including cancers, birth defects, and
genetic damage. The nominal annual excess cancer risk of the 100 mrem/yr peak dose
standard is 5.75 x 10"5, which the Agency has determined will protect public health and
safety. The risk of birth defects and genetic damage from exposures at 100 mrem/yr is
much smaller than the risk of cancer.
Comment 0368.15-1 indicates that EPA has attempted to downplay the effect of radiation
on human health. This is incorrect. In setting a dose rate limit for up to 1 million years, a
task unprecedented in U.S. regulatory history, EPA considered international guidance and
regulations. The great majority of those guidance and regulatory approaches urged caution
when establishing compliance standards over very long times because the uncertainty in
projecting doses is so great that quantitative limits of the type applied for shorter times are
not as reliable.
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Section 2 Dose Limits
Issue I: Use qualitative standards
1.	EPA should consider justifying qualitative performance standards based upon actual
measurements to be taken at prescribed future intervals. The future capacity of any agency
to regulate and enforce protection standards promulgated at this time is in all likelyhood
even more uncertain than the projections of exposure rates at those future times. The
emphasis should be on the safest disposal system we can engineer at this time, with
provisions for monitoring and improvement when (and if) such future capacity exists.
(Comment 0277-2)
2.	Furthermore, the EPA acknowledges that it considered setting a long-term standard of
100 millirem or 200 millirem. Yet, in justifying their decisions to choose the weakest
standard, the EPA essentially argued that given the time frame, there was essentially no
difference between 100, 200, and 300 millirem of exposure	That is, when taking
increasing uncertainties into account in the very long term, the effects of factors that would
distinguish projections of 100, 200, or 350 millirem per year within a 10,000 year time
frame are more difficult to identify clearly at very long times so that such projections may
be qualitatively identical to each other. Yet, this begs the question, if the EPA maintains
that these standards are essentially indistinguishable, why choose a number? (Comment
0368.10-6)
Response to Issue I:
The Energy Policy Act of 1992 requires EPA to "prescribe the maximum annual effective
dose equivalent to individual members of the public." Furthermore, the NAS
recommended that EPA establish "a standard that sets a limit on the risk to individuals."
(NAS Report p. 2). Therefore, the Agency does not have the discretion not to establish a
public health and safety standard in the form of a dose limit that prescribes the maximum
annual effective dose equivalent to individual members of the public
With respect to requiring qualitative performance standards based upon actual
measurements to be taken at prescribed future intervals (Comment 0277-2), we believe that
it is unreasonable to assume that there will be monitoring programs for Yucca Mountain in
place over the next 1 million years.
Section 2 Dose Limits
Issue J: Increase the proposed dose limit
1.1 believe the proposed standard is excessively conservative, goes well beyond what is
legally required, and is potentially environmentally counter productive because it may
unnecessarily reject the Yucca Mountain repository site thus forcing society to unknown
and potentially greater environmental risk waste management scenarios for spent nuclear
fuel and high level radioactive waste. There is no risk free method for managing
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radioactive waste. Unnecessary conservatism can result in de facto rejection of any
geologic repository site resulting in significant negative safety, security, public health,
environmental and economic impacts. Such unnecessary rejection, due to unrealistically
conservative standards, leaves no known methodology for ultimate disposition of
radioactive materials. Nuclear wastes exist, are currently being produced to support
important societal needs, and will likely increase in the future because of climate, clean air
and economic necessities. This current generation has an intergenerational responsibility to
future generations for a solution to the waste material being made today. Unnecessarily
stringent environmental standards for such unprecedented time periods can result in
needless refutation of an acceptable solution and force society into a no solution
alternative. Although strict very long term standards, as proposed, may sound
environmentally protective, they may actually be counterproductive to the environment
because they may force society into less environmentally benign nuclear waste
management approaches. Unnecessary rejection of the Yucca Mountain site with its
relatively low environmental impact for unknown approaches that our grandchildren will
have to develop is just irresponsible societal environmental action by this generation.
(Comment 0264-1)
2.	.. if EPA chooses to require a dose standard for the period of peak dose, the proposed
350mrem/yr standard should be increased to approximately the l,000mrem/yr level to be
consistent with radiation level risks that are commonly encountered in natural
environments, e.g. thorium sands and radon deposits, or occupational environments, e.g.
commercial airline workers. There is no need to require such a restrictive 350mrem/yr
standard when there are no discernable impacts at higher levels. Overly restrictive criteria,
like 350mrem/yr, increase the risk of rejection of a geologic repository and force society to
look for unknown solutions. (Comment 0264-3)
3.	The proposed radiation protection standards are far more restrictive than necessary.
There is no realistic way that the material to be stored there can pose a public health hazard
to people or the environment, even under extreme casualty conditions. (Comment 0269-1)
4.1 believe the proposed standard is excessively conservative, goes well beyond what is
legally required, and is potentially environmentally counter productive because it may
unnecessarily reject the Yucca Mountain repository site thus forcing society to unknown
and potentially greater environmental risk management scenarios for spent nuclear fuel and
high level radioactive waste.
If EPA chooses to require a dose standard for the period of peak dose, the proposed
350 mrem/yr standard should be increased to approximately 1,000 mrem/yr level to be
consistent with radiation level risks that are commonly encountered in natural
environments, i.e. thorium sands and radon deposits, or occupational environments, e.g.,
commercial airline workers. (Comment 0351-1)
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Response to Issue J:
We agree that our standards should provide a reasonable test of the overall safety of the
Yucca Mountain disposal system. However, our standards similarly do not have the
purpose of advancing geologic disposal as a concept. Our authority extends only to setting
public health and safety standards for the Yucca Mountain disposal system; they are not
based upon considerations of their impact upon other portions of the nuclear fuel cycle.
We believe we have balanced the factors important to regulatory decision-making over
very long times, the relative confidence that can be placed in projections over different time
frames, and the nature of the current generation's commitment to future generations, as
well as how that commitment can be demonstrated. Further, as discussed in more detail in
the preamble to the final standards and in other sections of this document, we believe that
the standards promulgated today will protect the health and safety of future generations
while recognizing the uncertainties involved in projecting doses for up to 1 million years.
Section 2 Dose Limits
Issue K: Use a graduated standard
1.1 do believe, however, that the proposed increase in the dose criterion at 10,000 years is
too large to be reasonable over the entire time out to one million years. Rather, I would
argue in favor of a more gradual increase to acknowledge that difficulties in projecting
performance (i. e., increases in uncertainties) should not be as great within a few tens of
thousands of years as they are beyond a few hundred thousand years.
Specifically, given the existing annual dose criterion of 0.15 mSv that applies for
the first 10,000 years, I support using an annual dose criterion of 1 mSv from 10,000 to
100,000 years and, with one caveat described in the following paragraph [see Issue M,
Comment 1], an annual dose criterion of about 3.5 mSv from 100,000 to 1,000,000 years.
(Comment 0186-7)
Response to Issue K:
We agree with the commenter that the uncertainties involved during the unprecedented
compliance period over which performance must be projected make an approach similar to
the suggestion appropriate.
The Court remanded the standards based upon its judgment that we had not been consistent
with the NAS recommendation of setting a standard for the time of peak dose within the
period of geologic stability (which the NAS said would be on the order of 1 million years).
Based upon preliminary information from NAS (NAS Report p. 6) and DOE, e.g., in the
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supplemental EIS, the peak dose will likely occur after several hundred thousand to 1
million years. In light of public comments, we have modified our approach and adopted a
1 mSv (100 mrem)/yr standard for the period between 10,000 and 1 million years. We
believe this standard is protective of public health and adequately addresses our concerns
regarding the increased uncertainty in long-term performance projections. Therefore, EPA
has decided to maintain the transition at 10,000 years for the reasons articulated in the
preamble for the final amendments and Section 4 of this document.
Section 2 Dose Limits
Issue L: Use a dose target
1.	Given the uncertainties in projecting performance of the Yucca Mountain facility over
very long times, I also think it would be better to round 3.5 mSv to one significant figure
(either 3 or 4 mSv), even if EPA does not specify a gradual increase in the dose criterion.
The difficulty I have with using 3.5 mSv is that a projected dose of 3.6 mSv would indicate
noncompliance but a projected dose of 3.4 mSv would indicate compliance when the truth
of the matter is that there is no significant difference whatsoever between those two doses.
Thus, regardless of the dose criteria that EPA chooses to apply beyond 10,000 years, they
should be presented in the regulations in such a way that it is clear that only one figure
(digit) is significant. For example, if 1 mSv were chosen, the regulations should specify 1
mSv (0.1 rem), rather than 1.0 mSv (100 mrem). (Comment 0186-8)
2.	.. .the Supplementary Information briefly considers an option of using a standard
expressed as a dose target, rather than a limit. In my opinion, EPA has not given this
option the consideration it deserves. Indeed, this may be an attractive option compared with
using dose criteria expressed as limits that must be met (with "reasonable expectation").
The attractiveness of using a dose target, rather than a dose limit, is laid out in the report
from the UK Environment Agencies (Docket No. OAR-2005-0083-0063) discussed in the
Supplementary Information. To be sure, the approach used in the UK presents its own
challenges, some of which are noted in the Supplementary Information. What I believe
EPA needs to appreciate about use of a dose target, without specifying a dose limit in
regulations, is this: The approach laid out by the UK Environment Agencies is largely the
same as the approach to regulatory decision making in cleanup of contaminated sites under
CERCLA (Superfund). Then, cleanup levels at each site are selected by a process of
negotiation among all stakeholders. Thus, regulatory decision making in the absence of
specified limits is something we have been through hundreds of times by now and is quite
familiar. It is not something new and untried. There is another parallel between cleanups
under CERCLA and disposal of waste at Yucca Mountain that is worth noting. Both are
concerned with pre-existing situations that must be dealt with one way or another. Even if
EPA does not wish to consider this option, I believe that EPA needs to be more thoughtful
in dismissing it. It has advantages, and it is an option that most stakeholders would be
familiar with, owing to striking parallels with the CERCLA decision process. (Comment
0186-20)
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Response to Issue L:
As set forth in Section 2, Issue I, EPA must establish a specific peak dose limit; it does not
have the discretion to adopt an amorphous standard. Further, not only does it fail to meet
the basic mandate of the Energy Policy Act of 1992, an amorphous standard also fails to
give NRC or DOE clear guidelines as to the necessary performance requirements for
licensing. Comment 0186-8 suggests that the dose standard be expressed in one significant
digit, presumably so the mean of the distribution of projected peak doses can be rounded to
show compliance with the standard. However we believe the "reasonable expectation"
principle employed in 40 CFR part 197 already gives NRC the flexibility and authority to
consider the entire record before it and consider all aspects of the performance projections
in finding a reasonable expectation of meeting the standard either has or has not been
provided. We believe the Commission will use this flexibility with full integrity and
cautiously. We do not believe that the Commission would issue a license unless it is fully
convinced that there is "reasonable expectation" that the disposal system will perform
acceptably.
Comment 0186-20 stresses the similarities between CERCLA sites and Yucca Mountain
and the practice of negotiating clean-up goals. As we stated on page 49038 of the preamble
to the proposed amendments: "We believe the circumstances involved in today's proposal
are significantly different from the situations addressed under Superfund or any other
existing U.S. regulatory program, and that it should be clear that comparisons between the
two are inappropriate." That, together with the legal requirements in the Energy Policy Act
of 1992, is why, despite the uncertainties involved, we need to establish a numerical limit.
Section 2 Dose Limits
Issue M: Peak dose calculation
1. Additionally, the supposed "peak" doses are not peak at all. They are merely averages of
hundreds of computer runs with different input assumptions and tweaking of scenarios.
Indeed, they are averages of different computer runs for the same point in time, rather than
averages of the peak dose from each scenario. Peak dose - highest calculated dose to the
public - which is what should be regulated by such a rule, is not at all. (Comment 0296-4)
Response to Issue M:
The commenter is referring to two calculational methods known as "peak of the mean" and
"mean of the peaks." As noted by the commenter, "peak of the mean" is a calculation in
which the mean of the results of "all computer runs" (or realizations) is calculated for
increments in time. This results in a curve that represents the mean (average) value
throughout the compliance period; where that curve peaks is the value used to compare to
the dose rate limit. The "mean of the peaks" refers to finding the maximum dose of each
realization, no matter when it occurs, and calculating the mean (average) of those values
for comparison to the dose rate limit. The Agency has specified that the peak of the mean
approach, termed the "peak mean dose" in 40 CFR 197.13, be used for the compliance
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determination, meaning that the peak of the curve that represents the arithmetic mean of the
distribution of all the projections will be used. We believe NAS intended the peak of the
mean be used, as indicated by its recommendation to assess compliance with the standard
"at the time of peak risk." (NAS Report p. 2) There is no "time of peak risk" if the mean of
the peaks is the measure of compliance.
The peak of the mean approach has the advantage of being a more realistic description of
the range of potential receptor dose rates at all points during the compliance period,
whereas the mean of the peaks approach cannot be considered to reflect the dose potential
for the RMEI at any particular time since it averages peak dose rates that are separated in
time. From a regulatory perspective, because it represents the evolution of the entirety of
the disposal system over time, the peak of the mean may provide a more meaningful basis
for decision-making. At each point in time, the progression of the individual realizations
and the mean dose curve can be more easily viewed in relation to one another as indicative
of "expected performance." The mean of the peaks, on the other hand, relies on the
combination of specific points of distinct realizations that may make it more difficult to
relate to the overall safety of the system, and the remainder of each realization is of no
consequence in the evaluation of that system. Except perhaps in the extreme situation
where all (or substantially all) of the realizations exceed the regulatory standard, it is not
clear exactly what information the mean of the peaks conveys about the disposal system as
a whole. There is further discussion of this issue in Section 7 of this document.
The Agency disagrees with the commenter's final sentence that indicates that the highest
calculated dose to the public should be used for compliance. The Agency's reasonable
expectation approach calls for extreme assumptions and results to be considered but not
overriding. Nor should a focus on "expected performance" be interpreted as meaning that
no person at any time will be exposed to doses above the standard. Therefore, a reasonable
approach is to use the results that indicate where the preponderance of the performance is
projected to be, i.e., neither the most pessimistic nor the most optimistic results. In
addition, the commenter's approach would not be in concert with the NAS Report in which
the NAS recommended using the mean of the calculations, not the theoretically highest
possible outcome. (NAS Report p. 123)
Section 2 Dose Limits
Issue N: EPA must explain how other contributions are considered
1.1 also want you to pay some attention to cumulative doses. With the nuclear industry and
the nuclear cycle having to do with nuclear power, the limit is 100 millirem from all — all
sources. And when you come in with the 350, which is very, very, high, I'm not sure that's
supposed to be added to background, which would now, I guess, include whatever is
emitting from the low-level dose site that's nearby from the Nevada Test Site, from other
nuclear activities out there. (Comment 0211.11 -3)
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2.	The 10,000 years standard for a repository at Yucca Mountain was, I believe, arrived at,
in part, by considering potential exposure to the residents of Amargosa Valley from
radiation releases from other sources, with each source being allocated a maximum annual
dose of 15 millirem. For the affected residents, these other source which would have the
effect of increasing exposure over and above natural levels. The other potential sources of
man-made exposure are the low-level radiological dump south of Beatty, the groundwater
contamination from the nuclear weapon testing activities at the NTS, and releases from the
wastes deposited in the bore-holes at the NTS. Radionuclide releases and migration from
the latter two sources are currently under active study by the DOE. If it had been the intent
of the EPA to have the post 10,000 year exposure limit (proposed to be 350 millirem for
the Yucca Mountain disposal facility) to include all sources of man-made radiation (i.e., the
Beatty dump, the NTS testing contamination and the NTS waste wells), this would have
been explicitly stated in the proposed regulation. In the absence of such a statement then
the EPA must consider that a radiological protection level of 350 millirem from each of
these radionuclide waste locations to be protective to the Amargosa Valley population after
10,000 years (i.e., a potential annual dose of 1.4 rem). EPA should identify in their
proposed regulation how these releases from multiple sources (which will occur in the
million year time frame) are to be considered such that the local residents are protected.
(Comment 0263-15)
3.	Neither portion of the "double-standard" addresses the multiple-pathway cumulative
exposure problem at the Yucca Mt. site, which is bracketed by the Beatty toxic waste
dump, already in possession of a plutonium plume, and the Nevada Nuclear Test Site,
home of over 1,000 nuclear bomb detonations. (Comment 0306-10)
4.	EPA is using today's background radiation to set a standard well into the future. Since
we know less about the future than the present, EPA should be assuming greater
background radiation levels than exist today. In the past 60 years, radiation levels have
been altered because of the actions of man and of government, such as the fallout and
effects from nuclear weapons testing and nuclear materials both in the United States and
other locations. The EPA rule assumes that background radiation levels will not change
over the period from 10,000 years up to one million years. There are many speculative
parts about making a rule to apply far into the future. One thing that should be clear to the
EPA is that today's conditions cannot be assumed to be the same in 300,000 years or a
million years. EPA should assume greater background radiation levels in the future than
today, and the proposed standard should reflect these conservative assumptions.
(Comments 0353-5 and 0361-5)
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Response to Issue N:
Pursuant to Section 801 of the Energy Policy Act of 1992, EPA's mandate is to set
standards that apply to radiation released from the potential Yucca Mountain disposal
system, not to quantify or require projection of potential exposures from other possible
sources.7 In addition, after considering the comments on the use of background radiation
to establish a quantitative dose standard and other technical factors, the Agency has
decided not to use background radiation as the basis for the 10,000- to 1-million-year
standard. Instead, the Agency has decided to establish a peak dose standard consistent with
the internationally recognized limit of 1 mSv (100 mrem)/yr. (Please see the preamble to
the final amended standards for further discussion of the new compliance period and dose-
rate limit.)
Section 2 Dose Limits
Issue O: Other dose limit comments
1.	EPA specifically chose not to set a dose standard beyond 10,000 years because no
"proof' was possible. When the court demanded that EPA set a standard beyond 10,000
years, because NAS requires it, EPA consistently passes the decision on to NRC (as if EPA
really doesn't want to be responsible for any decision beyond 10,000 years). (Comment
0113-1)
2.	What factors determine the radiation and what is the level? What assurance can the DOE
and EPA give the public that the 15-millirem level can be maintained for 10,000 years?
(Comment 0209.3-3)
3.	When we had our meetings with you, it's very difficult to know what we should have
talked about. We never in the world realized that you'd go to 350 millirem. The suggestion
was made that somebody had said perhaps 100 was a good idea. And we all said no. But
you couldn't possibly have thought that we meant that that was too low. So I don't know
where in the world that came from. (Comment 0209.14-4)
4.	We recommend that the proposed regulatory standards for the period of time beyond
10,000 years be adopted for the Yucca Mountain repository. However, for the
implementation of the standard, NRC should develop a probabilistic safety goal
comparable to those in use for the risk-informed regulation of nuclear power plants.
However, when issues are raised in the future that relate to the integrity of the repository
(such as possible evidence for historic water intrusion, earthquakes, or volcanic activity),
We note, however, that even if the Agency did have authority to address radiation released from
other sources in these standards and releases from the other sources actually reached the RMEI, the releases at
issue would not likely add contemporaneously to any impact on the RMEI. That is, the peak doses from the
sources cited by the commenters likely would not correlate with those from the repository. For example,
exposures from low-level waste operations would be expected to peak after a few hundred years, while the
expected peak doses from Yucca Mountain are most likely to occur at least hundreds of thousands of years
later.
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they should be addressed probabilistically against compliance with the probabilistic safety
goal. (Comment 0215-7)
5.	What limit did the NAS recommend? (Comment 0367.1-3)
6.	15 millirem additional to what? (Comment 0367.1-4)
7.	Why 350? (Comment 0367.2-5)
8.1 believe you should go [setting the dose limit] according to cancer incidence risks and
protect to standards like one in 10,000 for cancer incidence, not cancer fatalities because
fatality rates are changing all the time, fortunately coming down due to improved medicine.
(Comment 0368.3-9)
9. You must consider the pregnant women, the fetus, the - those who have suffered from
other illness, from age, in setting a radiation protection standard that will truly protect and
to be honest, to take a very strong position concerning the desirability of generating far
more radioactive wastes. (Comment 0368.4-4)
Response to Issue O:
We received a number of other comments or questions related in some way to the dose
level. Commenter 0113 suggests that we have not "set a standard beyond 10,000 years."
We have set such a standard at a level of 1 mSv/yr (100 mrem/yr), which is protective of
public health and appropriately addresses our concerns regarding the uncertainties
associated with assessing compliance for periods approaching 1 million years (see Section
6 of this document). The determination of compliance with that standard is NRC's
responsibility, as it has always been under the Nuclear Waste Policy Act of 1982 and the
EnPA of 1992. We have defined how the assessments are to be performed in certain
respects, such as the definition of the reasonably maximally exposed individual (RMEI)
and the treatment of features, events, and processes (FEPs) beyond 10,000 years (see
Sections 8 and 16 of this document). However, we have left the details of implementation
to NRC as the licensing authority.
Commenter 0209.3 asks basic questions regarding the calculation of dose and the level of
assurance that can be provided that our standards will be met. The primary factors
affecting radiation dose, in addition to the amount of the radionuclide present, are the type
of radiation emitted and the exposure pathway. Gamma radiation is the primary concern
for external exposures. Alpha and beta radiation are of limited concern externally, but are
the primary contributors to internal exposures if inhaled or ingested. The energy associated
with the radiation and which organs are preferentially exposed are also significant factors.
For example, some radionuclides when ingested will migrate to bone (e.g., strontium or
radium, which are chemically similar to calcium), the thyroid (i.e., iodine, which is
important for healthy thyroid function), or other specific organs. See Issue H of this
section, as well as Sections 5 and 11 of this document, for more discussion of this issue.
More information may also be found at http://www.epa.gov/radiation.
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The determination of compliance with our standards will be based on DOE's performance
assessments. NRC will determine whether there is a "reasonable expectation" that the
standards will be met before it may issue a license. In addition to quantitative dose
projections, NRC will also consider the other factors that are important to the overall
judgment of safety and how they are reflected in the performance assessment. For the
initial 10,000-year period, the ability of the engineered barriers (e.g., waste packages and
drip shields) to contain the waste and prevent releases will be of most importance, so
assumptions regarding those components of the repository will be most critical for that
period, when the thermal stresses are most significant. Examples of factors NRC will
consider in reaching its determination of "reasonable expectation" may be found in Docket
No. EPA-HQ-OAR-2005-0083-0376, p. 45.
Commenter 0209.14 expresses concern that we gave no indication in pre-proposal
stakeholder meetings of considering levels as high as 350 mrem/yr for the period beyond
10,000 years. The primary purpose of those meetings was to provide basic information on
the status of our rulemaking and to listen to the concerns and advice of stakeholders that
could influence our decisions, not to foreshadow regulatory decisions before the Agency's
internal review processes had been conducted. The level of 100 mrem/yr mentioned by the
commenter had been suggested in a report by the Electric Power Research Institute (EPRI)
(Docket No. EPA-HQ-OAR-2005-0083-0087). That level is consistent with the overall
public dose limit for practices involving radioactive material that is recommended and
accepted by international organizations such as ICRP, IAEA, and NEA, as well as by NRC,
DOE, and NCRP. We have established that level as our final individual-protection
standard for the post-10,000-year period. See Section 14 of this document for more
discussion of public outreach.
Commenter 0215 suggests that "NRC develop a probabilistic safety goal comparable for
those in use for the risk-informed regulation of nuclear power plants." The commenter's
suggested approach appears to be as a supplement to the individual-protection standard to
be assessed using the RMEI (the commenter also supports the probabilistic approach
recommended by NAS). In this approach, the health detriment to the wider population
from releases from the Yucca Mountain disposal system at the level of the standard would
be compared to the "natural incidence of death." Below a specified fraction of that rate, the
probabilistic safety goal would be met. We have established a standard to limit doses to
individuals, as directed by the EnPA. Further, EnPA Section 801(a) specifies that the
public health and safety standards we establish "shall be the only such standards applicable
to the Yucca Mountain site." We note, however, that NAS concluded that an individual-
risk (or dose) standard would be sufficient to protect the wider population. (NAS Report p.
65)
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In response to Commenter 0367.1, NAS identified "the spectrum of regulations already
promulgated that imply a level of risk, all of which are consistent with recommendations
from authoritative radiation protection bodies" for EPA's consideration, among which were
the 100 mrem/yr public dose limit recommended by ICRP. (NAS Report p. 49 and Tables
2-3 and 2-4) Consistent with this discussion, NAS suggested as "a starting point for EPA's
rulemaking" an annual risk range of 1 in 100,000 to 1 in 1,000,000. (NAS Report pp. 5, 49)
NAS's starting risk range is consistent with the 15 mrem/yr level we had established in 40
CFR part 191 and used in other applications, so we viewed the NAS "recommendation" as
supporting that level at Yucca Mountain for the initial 10,000-year period. NAS explicitly
declined to recommend a final risk level for the time of peak risk, viewing that as a policy
decision best left to the standard-setting authority (EPA): "determining what risk level is
acceptable is not ultimately a question of science but of public policy." (NAS Report p. 5)
Both the 15 mrem/yr standard for the first 10,000 years and the 100 mrem/yr standard
beyond that time refer only to releases of radionuclides from the Yucca Mountain disposal
system. Natural background sources and other exposures caused by human activities are
not included in those dose levels.
In response to Commenter 0367.2, we note that the comment is now moot. We are
establishing 100 mrem/yr as the final dose standard to apply for the post-10,000-year
period. This level is consistent with the overall public dose limit recommended and
adopted both internationally and domestically today, and as such provides a clear basis for
determining that our standard will protect public health and safety in the far future. Most
residents of Amargosa Valley would be expected to receive much lower exposures than the
RMEI, if any, from Yucca Mountain.
Commenter 0368.3 recommends using cancer incidence as a benchmark for regulation,
rather than fatality, because fatality depends on factors such as the availability of effective
medical treatment. We discussed this question in our 2001 rulemaking, and noted that
"NAS concluded that nonfatal cancers are more common than fatal cancers. Despite this
conclusion, NAS cited an ICRP study that judged that non-fatal cancers contribute less to
overall health impact than fatal cancers 'because of their lesser severity to affected
individuals.' (NAS Report pp. 37-39)". (66 FR 32081, June 13, 2001) Based on the factors
we use, both the incidence and fatality rates associated with 15 mrem CEDE/yr are
approximately 3 x 10"4, accounting for rounding differences, which is consistent with the
Agency risk range. The overall factors we employ were reaffirmed by the recent BEIR VII
report (Docket No. EPA-HQ-OAR-2005-0083-0087).
As discussed in the preamble to the final rule and Issue B of this section, however, we do
not believe it is reasonable to view the post-10,000-year peak dose standard of 100
mrem/yr from the perspective of the Agency's traditional risk-management framework
(typically applied to situations where results can be confirmed, modeling is utilized on a
more limited scale, or institutional controls are more applicable). We would not view a
projected dose of 100 mrem/yr in the far future, with all the attendant uncertainties, as
comparable to a 100 mrem/yr dose incurred today, or even projected to occur within 10,000
years. Although NAS explicitly referred to risk as "the expected value of a probabilistic
distribution of health effects" (NAS Report p. 4), the use of long-term projections of risk as
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a measure of future health detriment is discouraged by ICRP (in part because of reasons
cited by the commenter, such as advances in medical treatment). ICRP recognizes,
however, that relation of projected risk to future health detriment is common practice and
somewhat more defensible for periods up to about 10,000 years. (ICRP Publication 81,
Docket No. EPA-HQ-OAR-2005-0083-0417, Paragraphs 41 and 71) Therefore, while we
believe it is reasonable to discuss the 15 mrem/yr 10,000-year standard in terms of risk and
relate it to overall Agency policy, we are more cautious in applying current risk estimates
to the 100 mrem/yr standard applicable for the period beyond 10,000 years. We estimate
the nominal annual risk associated with 100 mrem/yr, based on current risk conversions, is
5.75 x 10"5, which we find to be comparable to the range of risks represented by the
domestic and international regulations that NAS suggested EPA consider. (NAS Report p.
49 and Tables 2-3 and 2-4) As noted above, as a matter of Agency policy, the estimated
lifetime risk associated with 15 mrem/yr is considered consistent with the risk range even
though it is slightly higher than 10"4. When time frames on the order of 1 million years are
considered, the level of risk represented by the 100 mrem/yr peak dose standard is
reasonable, and we conclude that our final peak dose standard will protect public health and
safety. See the preamble to the final rule, as well as Issue H of this section and Section 5 of
this document for more discussion of risk.
Commenter 0368.4 urges us to use more vulnerable populations in setting standards. In
relating dose and risk to health effects, we use factors that incorporate considerations of age
(including fetal development), gender, and other factors. As we stated in our 2001
rulemaking, although exposures in utero appear to have greater impact, the relative length
of the period of exposure compared to the lifetime tends to reduce their significance,
particularly at low dose rates (such as background radiation). See also Issue H in this
section for discussion of radiation risks and their effects on children's health.
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Section 3 Background Radiation
Issue A: Oppose use of natural background radiation to establish the dose limit
1.	The new standard is based on EPA's unstudied view that it is appropriate to expose
unconsenting local populations to high levels of radiation so long as they do not exceed the
highest levels of natural background radiation tolerated in the most radiation-prone states.
(Comment 0103-1)
2.	Why should EPA allow people in the Yucca Mt. vicinity be exposed to 350 mrem/yr in
the future if they have no choice in the matter? Just because Colorado is nearby and has
700 mrem/yr in some areas is no reason... .1 see no ethical or logical reason to allow man to
expose other men to any additional radiation at all much less 350 mrem/yr which a lot of
people are not exposed to "naturally"... .To me, your reasoning is like saying
(hypothetically) "Rockfalls kill 270 of the people hit by them every year, so it is ok for man
to stone 270 of the people to death every year". Does that make any sense at all? I hope not.
Just because Mother Nature does harm doesn't give man the right to do it too, does it?
(Comment 0113-4)
3.	EPA's proposed 350 millirem dose limit would be in addition to natural background
radiation exposure levels (which according to EPA's definition, includes indoor radon, an
artifact of construction). In other words, the EPA wants to allow future generations to be
exposed to the equivalent of twice the level of background radiation. (Comments 0130-2;
0195-2)
4.	EPA tries to convince the public that radiation exposures, no matter how high, can
justify additional exposure of Nevadans if it can be shown that somewhere those levels
exist naturally, but this is not how EPA should or has written regulations. There is no
doubt that EPA's traditional thinking went out the window regarding Yucca Mountain.
(Comment 0145-1; 0257-4)
5.	EPA's proposed rule offers a convoluted and arbitrary rationale for what its second-tier
standard should be. EPA suggests that "given the large uncertainties surrounding the
outcomes at these unprecedented time frames," it is reasonable to set a standard based on
natural background radiation levels in one of the nation's more radioactive states: not
Nevada, where Yucca Mountain actually is, but Colorado. On this rationale, EPA
concludes that allowing 350 millirem/year of anthropogenic exposures to Nevada's citizens
is appropriate. EPA's background rationale is flawed. (Comment 0226-48)
6.	There is good reason for EPA's (and other standard setting agencies') past reluctance to
use natural background or variations in natural background as a basis to establishing
acceptable levels of risk. A risk is not acceptable just because it is "natural." Societies
undertake extraordinary measures to eliminate or mitigate such natural hazards as
hurricanes, tornados, and toxic substances found in nature like botulism. The concept that
variations in natural background pose acceptable risks is based on the highly doubtful
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premise that people are knowledgeable about these radiation levels, and the associated
health effects of radiation, when they choose where to live or work. Finally, even if these
comparisons were relevant, EPA cannot explain how they are uniquely relevant to the
period after 10,000 years. (Comment 0226-51)
7.	Similarly, EPA's implication that it can safely create Colorado-like levels of exposure in
Nevada because people live in Colorado is untenable. Simply because a risk exists
naturally in one location does not mean that it is acceptable or "safe" for humans to create it
somewhere else. We would never accept as "safe" a human project that creates San-
Francisco-like levels of earthquake risk in Chicago, or that subjects Washington D.C. to the
risks of hurricane damage that Miami naturally faces, even though millions of people live
in the at-risk areas. Similarly, EPA has no basis in implying that because people live in
Colorado now, the radiation levels they may face may acceptably be created elsewhere.
(Comment 0226-54)
8.	In setting other health and safety standards, EPA has frequently rejected comparisons
with natural background. Earlier this year, EPA rejected the concept that emissions of
hazardous materials should not be regulated if the resulting levels in the environment are
within the bands of variation in ambient background levels. 70 FR 19992, April 15, 2005
(rule limiting emissions from coke oven batteries), citing with approval 54 FR 38044,
September 14, 1989 (rule limiting emissions of benzene and other hazardous materials).
EPA also rejected a natural background radiation rationale when it set health-based
emission standards for radioactive materials under a statutory regime (the Clean Air Act)
identical to the Atomic Energy Act, 54 FR 51654, December 15, 1989, and when it set
standards limiting radioactive emissions from uranium mills, 51 FR 42573, November 2,
1986. EPA rejected comparisons with natural background when it proposed changes in
guidance to all federal agencies on the formulation of radiation protection standards. 66 FR
66414, December 23, 1994 ("although the average level of exposure to natural background
provides perspective, it does not, however, provide justification for the RPG [Radiation
Protection Guidance], since it represents an uncontrollable source of risk, and the RPG
applies to controllable sources"). (Comment 0226-55)
9.	Additionally, EPA's rationale misunderstands the role of radon in creating natural
exposures in Colorado and elsewhere. As EPA acknowledges, most natural exposures, in
Colorado and elsewhere, result from radon. In Colorado radon accounts for approximately
87% of total radiation exposure. S. Cohen and Associates, Assessment of Variations of
Radiation Exposure in the United States (2005), OAR-2005-0083-0077, at 4. But radon
exposures are locally variable, site-specific, and amenable to mitigation; a person lives with
radon risk because either they are ignorant of that risk or they have made a conscious
choice not to deal with it. (Comment 0226-56)
10.	It was interesting to follow EPA's development of the dose requirement after 10,000
year. Given that the EPA Web site has a whole section devoted to radon exposure, radon
health hazards, and potential mitigating measures for indoor radon. (The posting of the
announcement of National Radon Action Month, 2005 was enlightening as the text starts
out by reminding our Nation of the serious danger that radon gas poses in our home. It
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continues by stating that it encourages all Americans to join in this crucial effort and learn
more about the health risk posed by radon, test for it, and where warranted take steps to
reduce expose to it). Other pages of the EPA web site tells us how we can mitigate the
effects of radon exposure by relatively simple and inexpensive measures to reduce indoor
radon concentrations to the much lower outdoor concentration levels (around 0.4 pCi/L). In
fact the document cited by EPA in the draft regulation (Assessment of Variations in
Radiation Exposure in the United States, page 12) tells about the large mitigation effort that
has taken place during the last 10-15 year in regions where indoor radon levels are 4 pCi/L
or greater, which include Colorado, were not considered in the data presented and
subsequently used by EPA in the proposed regulation. This statement regarding data
applicability indicates that the proposed EPA regulation is based on old and not currently
valid data. This is not a sound legal or scientific basis for a regulation governing the public
health and wellbeing. Given the high current rate of applying radon mitigation, it is likely
that mitigation will be universal used in dwellings before the proposed repository is closed.
Therefore, on one hand EPA is really concerned about the health risk associated with the
present day level of exposure from indoor radon in States such as Colorado where the
expected indoor radon concentration is abnormally high (>4 pCi/L). While on the other
hand EPA is setting a regulatory standard for Amargosa Valley residents for more than
990,000 years based on this acknowledged unnecessarily excessive present day exposure to
radon for Colorado residents (i.e., in the highest 10 % of the nation). These positions seem
to be contradictory in terms of protecting the wellbeing of all present and future citizens of
our nation. The Amargosa Valley resident is proposed to be given the radiological
protection that is based on the annual natural background dose of 700 millirem received by
an average resident of Colorado (47.5 millirem/yr cosmic, 42.6 millirem/yr terrestrial, and
610 millirem/yr radon) over and above the estimated level of 350 millirem for Amargosa
Valley residents (100 millirem/yr from terrestrial and cosmic sources plus 250 millirem/yr
from radon). However, according to the EPA, the informed resident of Colorado will know
about the radon hazard and will have taken steps to mitigate its effect to a degree (EPA
acknowledges that there are a large number of household mitigations being undertaken
every year). The radon contribution to dose for Colorado residents can be reduced by a
about an order of magnitude to about 61 millirem per year based on EPA figures of typical
outdoor radon concentrations of 0.4 pCi/L and unmitigated indoor concentrations in
Colorado of over 4 pCi/L. The Colorado resident who has followed, because of health and
safety reasons, the EPA safety guidelines for radon will receive an annual dose of 151.1
millirem (47.5 millirem/yr cosmic, 42.6 millirem/yr terrestrial, and 61. millirem/yr radon).
Thus, to give the Amargosa resident the natural radiological protection that an aware and
radon mitigated Colorado resident has today (using EPA recommended radon alleviation
measures) means that the total annual dose could be increased to 151.1 millirem per year
from a present day Amargosa Valley natural background plus mitigated radon dose of 125
millirem per year. Thus the allowable additional radiation dose (i.e., Colorado annual dose
minus the Amargosa Valley annual dose) from releases from the proposed repository
would be 26 millirem per year rather than the non-radon mitigated increase proposed of
350 millirem per year. Thus if EPA applies a consistent exposure logic the future additional
dose from a repository then this argument would appear to support not quite doubling the
present 10,000 years annual dose standard of 15 millirem. (Comment 0263-18)
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11.	It is ethically unacceptable to set public health and safety standards based on levels of
background radiation in the particular vicinity. All US citizens deserve the same level of
protection regardless of where they live. Levels of other toxicants vary across the US, e.g.,
high levels of mercury or arsenic in drinking water. Are we going to allow higher levels of
these in some areas than in others? (Comment 0293-12)
12.	The proposed rule makes entirely inappropriate reference to doses from natural
background radiation, estimated by EPA in the proposed rule as 350 millirem per year
(when radon gas exposures are included). Yes, we live in a sea of radiation from which we
cannot escape. That doesn't mean it is safe. The National Academy of Sciences, as
discussed above, estimates that 350 millirem/year of background radiation produces a
cancer in roughly 3% of us. In other words, 9 million Americans (out of a current
population of-300 million) will get a cancer from their exposure to background radiation.
Since -40% of us will get cancer, that means that about 7% of U.S. cancers are attributable
to background radiation. Adding to that another 350 millirem per year, on top of the
already lethal background dose we can't escape, just as a political favor to a powerful
industry, is unacceptable. (Comment 0296-6)
13.	The proposed rule implies that the proposed Yucca dose would be less than or equal to
background radiation. No. It would be on top of background, roughly doubling the dose
those members of the public get, and significantly increasing the numbers of cancers in the
exposed population. If we determined what is acceptable pollution or deaths based on what
cancers are produced from background radiation, all modern environmental standards
would go out the window. If this rule is approved, every polluter - every pesticide
manufacturer, every smelter, every chemical factory - will come in and demand that they
be permitted to release orders of magnitude higher levels of carcinogens. If it is OK to let
the nuclear industry give doses with a risk of 1 in 36 rather than 1 in 10,000 to 1 in a
million, then every other polluter will demand the "right" to produce cancers in the
innocent public at those astronomical levels. (Comment 0296-7)
14.	EPA claims that the 350 millirem/year exposure limit is an acceptable level of risk
since it is only slightly higher than that already received from natural-background radiation.
What the EPA rule does not take into account is that individuals exposed to radiation from
Yucca will receive these doses in addition to, not in place of, background
radiation.. .Reports from the United Nations Scientific Committee on the Effects of Atomic
Radiation, the International Atomic Energy Agency and other scientific groups have
already established that natural-background radiation causes about 3 percent of fatal
cancers - roughly 18,000 U.S. deaths annually. (Comment 0301-6)
15.	No U.S. or international regulations use background radiation to set public health
standards for radiation exposure. (Comment 0302-3)
16.	About 3 percent of American public will get a cancer from background radiation, which
is equivalent to almost 9 million people of the current U.S. population. Of the fatal cancers
in the U.S., approximately 7% are attributable to exposure to background radiation.
(Comment 0302-4)
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17.	EPA incorrectly argues that a radiation standard of 350 millirems per year, in addition
to the presumed background radiation level in Amargosa Valley (350 millirems per year),
is protective of the public, because the total (700 millirems per year) is equal to an inflated
estimate of the current average background radiation in Denver, Colorado. This is not a
sound basis for EPA's standard, because not only is background radiation not a safe level
of exposure, but background levels of radiation across the U.S. are highly variable, with
Colorado being significantly above the average. (Comment 0302-5)
18.	While the concept of matching "background" radiation seems benign, it should be
noted that the 350 millirem limit is for a maximum exposure nationwide. Even at Yucca
Mt., next to the Nuclear Weapons Test Site, annual background exposure is about 110.
Furthermore, background radiation causes serious cancers each year, skin cancers,
melanomas and more, especially in this sunny desert region. (Comment 0306-9)
19.	In addition, the City does not believe it is appropriate to develop radiation standard;
based on the highest levels of natural background radiation tolerated in the most radiation-
prone states. Developing a radiation health protection standard in this way is not condoned
by any other standard-setting body in the world, including the National Academy of
Sciences. (Comment 0341-8)
20.	Groundwater is the most important receptor, not background levels of radiation, as a
benchmark. (Comment 0367.2-29)
21.	The EPA has said that this is the same as background radiation. From our perspective,
clearly it is on top of background radiation. (Comment 0368.2-7)
22.	First, it is completely false to claim that the level of radiation is safe as long as it does
not exceed the highest levels of background radiation in the highest radiation prone states
such as Colorado. Background levels of radiation across the U.S. are highly variable with
Colorado being significantly above the average. No U.S. or international regulations use
background radiation to set public health standards for radiation exposure. (Comment
0368.6-3)
Response to Issue A:
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule. We received a significant number of comments taking issue with the
concept of using background radiation as an indicator of "safe" levels of exposure from an
engineered facility. We also received additional information that provided insights into our
consideration of background radiation. For example, monitoring stations operated by the
Desert Research Institute provided monitoring data indicating that the unshielded (outdoor)
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background radiation from cosmic and terrestrial sources in Amargosa Valley is roughly
110 mrem/yr. Commenters 0357 and 0359 also informed us that roughly 90% of the
population in Amargosa Valley lives in mobile homes, which has implications for indoor
radon exposures. Other commenters supported the use of a different factor for converting
radon concentrations into dose.
In considering these comments, as well as those taking issue with the overall premise
described in the proposal, we found the relatively simple approach used in the proposal
evolving into a more complex undertaking requiring numerous decisions where science did
not provide a clear answer. Indoor radon estimates presented the greatest challenge, and
also represented the highest proportion of overall background radiation. Complicating
factors included multiple ways of calculating radon dose, the prevalence of mobile homes
in Amargosa Valley, limited data sets primarily from the early 1990s, and data for
individual counties in a different format than State-wide data. We concluded that there was
no generally agreed-upon approach in the context of Amargosa Valley for incorporating
indoor radon exposures into an analysis of background radiation that would lead to a
regulatory standard.
We continue to believe that references to natural sources of radiation can provide useful
insights into the "significance of' projected doses (in IAEA's words) over hundreds of
thousands of years. For example, as noted above, 100 mrem/yr is roughly the value
reported by the Desert Research Institute for cosmic and terrestrial radiation at Amargosa
Valley (unshielded). When shielding from buildings is considered and indoor radon doses
are estimated using a more conservative conversion factor suggested by some commenters,
100 mrem/yr is at the low end of overall background radiation estimates in Amargosa
Valley and nationally. Within the State of Nevada, the difference in average estimates of
background radiation for counties is greater than 100 mrem/yr. (Docket No. EPA-HQ-
OAR-2005-0083-0387) This suggests that 100 mrem/yr can be considered to be a level
such that the total potential doses incurred by the RMEI from the combination of
background radiation and releases from Yucca Mountain will remain below doses incurred
by residents of other parts of the country from natural sources alone. It may also be noted
that the 1 mSv/yr (100 mrem/yr) public dose limit recommended by ICRP is itself related
to background radiation. (ICRP Publication 60, Docket No. EPA-HQ-OAR-2005-0083-
0421, paragraphs 190, 191) However, in the absence of compelling reasons for selecting
specific background radiation estimates and points of comparison, we conclude that
comparing background radiation estimates from specific locations does not provide a clear
or sufficient basis for a regulatory compliance standard applicable to the Yucca Mountain
disposal system.
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Section 3 Background Radiation
Issue B: Support the use of natural background radiation to establish the dose limit
1.	These levels have not been found to cause harm to human health. If you question this
information, then it behooves you to develop the data to support the alternative view, and
you owe such to the American people. If you accept natural world levels, then you have no
basis for setting any limits that are less than these ranges allowing for a reasonable safety
margin and certainly no basis for alarming the American people Above natural radiation,
we are already subjecting ourselves to some 60+ mrems with no apparent health danger,
and will increase this. (Comment 0100-1)
2.	The reason the mean is larger than the median is due to the fact that the distribution of
performance assessment dose results is not symmetric about the most probable value but
rather is skewed to high values. The infrequent larger values can more strongly influence
the mean than the median. The same skewness feature exhibited by performance
assessment doses characterizes the distribution of doses from indoor radon. To be
consistent the EPA should have used median values rather than mean values for indoor
radon contributions to the background dose in deducing the excess background Colorado
residents receive as compared to Amargosa Valley residents. The result of such a
calculation gives approximately 200 mrem/yr rather than 350 mrem/yr. (Comment 0183-1)
3.	The new proposed limit for the period 10,000 to 1,000,000 years after closure of Yucca
is a good start! However, with all the conservative assumptions that will be made in
modeling the radiological releases from Yucca over that period, the actual exposures will
be much lower than the modeled exposures, so limiting the MODELED exposures to the
national average is needlessly restrictive. Perhaps a more appropriate limit would be the
95th or 99th percentile of the natural background exposures that U.S. Citizens accept as
part of everyday life. (Comment 0187-1)
4.	Radiation is a naturally occurring substance which every person on Earth is exposed to
every day at some level - from X-rays in hospitals to granite rocks in some tunnels to
airplane flights high above the atmosphere's protection. Setting a lower radiation level
would not significantly change the additional health risk to people near the storage facility.
(Comment 0193-2)
5.	People in the U.S. and elsewhere have lived in higher-than-average radiation
environments, such as Colorado with 700 millirem per year average, as well as individuals
who have been overexposed to low-level radiation, such as more than 35,000 nuclear
shipyard workers, have been shown to have lower cancer rates and increased longevity. In
other words, many studies have indicated that radiation at these levels is good for people,
not the converse. So it's been from tens to hundreds of billions to ensure a near-zero
exposure is a waste of the public's money. This isn't the government's money we're
discussing here; it's mine, it's ours, and it's yours. (Comment 0209.9-2)
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6 Because the revised proposal for a dose limit of 350 mrem per year for the period past
10,000 years is comparable to levels already experienced in other parts of the country, it
makes good sense. (Comment 0217-5)
7.	Lincoln County is also concerned that EPA has chosen to utilize the levels of natural
background radiation in Colorado (averaging 700 mrem) in concluding that the addition of
350 mrem of exposure resulting from Yucca Mountain to natural background radiation in
the vicinity of Yucca Mountain is acceptable ... Use of Colorado levels of natural
background levels of radiation might be appropriate if the Yucca Mountain project were
being proposed in Colorado .. EPA should consider the Yucca Mountain repository as
being allowed to only contribute an incremental increase in exposure risk which is
consistent with the variation in natural background radiation in the vicinity of Yucca
Mountain. (Comment 0219-3)
8.	In fact, 350 mrem per year is within the range of variations in natural background that
exist within the State of Nevada which range from a low of 200 mrem per year in Clark
County to 680 mrem per year in Pershing County. Moving from low to high natural
background areas in Nevada and across the United States is not generally perceived to
represent a radiological health risk. Radiation levels in this range are generally believed to
be well below the point at which public health and safety would be compromised.
Furthermore, the 350 mrem per year standard is not at odds with the 1995 NAS Report or
the court mandate in the NEI decision. (Comment 0298-14)
9.	The proposed rule prescribes a dose limit to be used beyond 10,000 years that is based
on current average annual background radiation levels in Amargosa Valley, Nevada, and in
Colorado. If those background values are higher now, or in 2000, say, than they were in
1900, because of Hiroshima, Nagasaki, atmospheric nuclear weapons testing, Chernobyl,
ongoing reactor plant operation, etc., then would it not be appropriate to extrapolate those
increases; i.e., to accumulate the century-on-century increases in average annual
background radiation in Amargosa Valley and Colorado out to 10,000 years and beyond?
Would using those larger extrapolated values not be more consistent with the "comparison
with background radiation levels" rationale that undergirds the new 350 mrem/year limit?
Indeed, the extrapolation should perhaps not be a linear one, given (based only on my
cursory survey of the past 10,000 years) (Comment 0307-1)
10.	The Department agrees with EPA that it is appropriate to consider potential exposures
from natural sources of radiation in establishing the acceptability of a peak dose standard
for Yucca Mountain.. .Relating the level to the variations in background radiation, rather
than the average, gives a clearer sense that these levels are routinely accepted by society
and do not influence an individual's decision to live in one part of the country to another.
(Comment 0352-19)
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Response to Issue B:
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule.
We disagree with the suggestion in Comment 0209.9-2 that there is no utility in regulating
low-dose radiation. We realize that the question of health effects resulting from low-dose
radiation remains unresolved, although much work is being done in this area. To say this
question is unresolved, however, is not to say that that radiation health effects are only
hypothetical. The NAS in its BEIR VII report concluded that there is insufficient evidence
at this time to abandon the linear no-threshold approach (i.e., that any incremental radiation
exposure carries a proportionate increase in risk). (Docket No. EPA-HQ-OAR-2005-0083-
0430) From a regulatory perspective, the linear no-threshold approach provides a prudent
framework or developing cautious, but reasonable, radiation protection requirements.
Section 3 Background Radiation
Issue C: Indoor radon is not natural background radiation
1.	Includes home radon exposure in calculations of natural background levels used to set
thresholds, a practice never done in such calculations because home radon exposure is
routinely mitigated. (Comment 0103-3)
2.	EPA misleads the public by implying that the level is set at truly "natural" background
levels. EPA's own documents show that EPA has included man-made sources of radiation,
such as indoor radon exposure, in its estimates. To call this "natural" is simply misleading.
(Comment 0293-11)
3.	EPA also improperly includes indoor radon exposure as part of its estimates of natural
background radiation. Radon is normally never included as part of background dose,
because indoor radon exposure is a man-made public health risk. (Comments 0145-3 and
0302-6)
4.	Indoor radon is a technological artifact and not part of natural background. Excluding the
indoor radon component, but retaining all other aspects of the EPA proposed rule, would
lower the limit from 350 mrem to approximately 100 mrem per year. (Comment 0314.1-2)
5.	The Toxic Substances Control Act recognizes that indoor radon is an artifact of building
construction and sets a long-term goal of reducing radon levels indoors to those
experienced outdoors. Hence, including the present level of indoor radon in natural
background is contrary to the intent of this law.
Specifically, the Toxic Substances Control Act states that
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"the national long-term goal of the United States with respect to radon levels in
buildings is that the air within buildings in the United States should be as free of
radon as the ambient air outside of buildings."
It is reasonable to assume that this goal could be met within the next few hundred
years as the building stock in turned over and that, therefore, long before 10,000 years, the
average population exposure to the US population will have been reduced to something
closer to 100 millirem per year from its current value of 300 millirem per year. Thus the
inclusion of radon doses in the proposed rule appear to be inconsistent with both the spirit
and the letter of this section of the law.
Following the passage of the section of the Toxic Substances Control Act in which
the "national long-term goal" was set forth, the NCRP issued a report on radon control
technologies in which they concluded that the information presented in this report shows
that there is a variety of methods available for the control of radon inside houses. All
systems can be effective when properly installed, but the best performance is achieved by
active soil ventilation techniques. For new houses being planned or under construction, the
installation of barriers between the soil and the house can be very effective. Properly done,
this approach will solve the problem for the duration of the use of the house. (Comment
0314.1-3)
6. The inclusion of indoor radon levels as part of "natural background radiation" is not
scientifically correct and fails to take into account both the letter and the spirit of current
U.S. law (see below). This inappropriate inclusion of radon has led the EPA to draw
erroneous conclusions regarding the regional variation in background exposures as part of
the proposed rule.
The "average annual effective dose equivalent to individuals in the U.S. population"
as estimated by the National Council on Radiation Protection and Measurements includes
200 millirem from radon and its decay products and 100 millirem from other sources such
as cosmic rays and the ingestion of primordial radionuclides. The DOE has estimated that
the exposure of people in the Amargosa Valley is equal to the average exposure reported by
the NCRP, while the EPA has estimated a higher radon dose of 250 millirem per year.
The exposure to indoor radon, which accounts for two-thirds of the average
population exposure in the United States, is, however, a result of human activities and not a
result of natural processes alone. As noted by the National Research Council in 1999
"Many human activities - such as mining and milling of ores, extraction of
petroleum products, use of groundwater for domestic purposes, and living in
houses - alter the natural background of radiation either by moving naturally
occurring radionuclides from inaccessible locations to locations where humans
are present or by concentrating the radionuclides in the exposure environment."
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The National Research Council considered indoor radon to be a "technologically
enhanced naturally occurring radionuclide [TENORM]." The treatment of other TENORM
from a radiation protection standpoint is thus illustrative in the present context. For
example, playground equipment and fences contaminated with TENORM waste from the
oil industry containing radium has been found at a number of locations in Mississippi and
Louisiana. Earlier, a Federal Court held Chevron Oil liable for damages to workers at a
salvage company for Chevron's failure to conduct adequate inspections of the equipment
and to warn the workers about the possible risks. Exposure to these TENORM materials
was not considered to be natural background exposure despite the fact that the
radionuclides involved were all naturally occurring. The EPA has itself referred to indoor
radon as a technologically enhanced naturally occurring radionuclide and has highlighted
the mechanisms by which the construction of homes and other buildings cause radon to
build up to higher levels than would be experienced outside. Because this exposure to
indoor radon is a result of human activity, it is scientifically incorrect to combine it with the
exposure to unavoidable background sources such as cosmic rays. Comparing indoor radon
to background radiation is like comparing taking a shower to getting wet from rain. The
EPA is aware of this legally mandated goal, and, since 1994, has published technical advice
for how to limit radon levels in new and existing homes as well as in new schools and other
large buildings. In fact, the EPA's 2005 Citizen's Guide to Radon: the Guide to Protecting
Yourself and Your Family from Radon notes that
"Radon reduction systems work and they are not too costly. Some radon reduction
systems can reduce radon levels in your home by up to 99%. Even very high
levels can be reduced to acceptable levels."
Already, people living in well-constructed buildings on upper floors are exposed to indoor
radon at a level that is not significantly different from outdoor levels.
Significantly, the exclusion of indoor radon from the assumed background radiation
level is consistent with the recommendations of the International Commission on
Radiological Protection. In its 1990 recommendations, the ICRP excluded the contribution
from indoor radon in its choice to use 100 millirem per year as the typical average "annual
effective dose from natural sources." The ICRP was even more explicit in its view on this
matter in its draft 2005 recommendations. In this report the ICRP stated that
"The Commission considers that the annual effective dose from natural radiation
sources, and its variation from place to place, is of relevance in deciding the levels
of maximum constraints that it now recommends. The existence of the natural
background of radiation does not provide any justification for additional
exposures, but it can be a benchmark for judgment about their relative importance
and the need for action. The Commission uses the background dose without
the radon contribution because that component is significantly enhanced by
human activities and is thus subject to recommendations from the
Commission for its control at home and at work."
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The Commission went on to caution that "[ejxposures that are within the natural
background range are legitimate matters for concern, sometimes calling for significant
action."
There is no scientific or legal basis for the EPA to consider exposures to indoor
radon as part of natural background radiation. The proposed rule has not cited any and has
not addressed legal and scientific view to the contrary. The final rule should exclude the
contribution of indoor radon from its discussion and use a reasonable value for natural
background radiation of about 100 millirem per year as estimated by the National Council
on Radiological Protection for the U.S. population and in line with the recommendations of
the International Council on Radiological Protection for a global average. The use of 100
millirem would also be consistent with the estimated exposure from non-radon sources for
people living in the Amargosa Valley reported by the DOE. The existence of this
background radiation does not provide a justification for any increase in the allowable level
of exposure for this or future generations. (Comment 0314.1-13)
7.	White Pine County is also concerned that EPA has chosen to utilize the levels of natural
background radiation in Colorado (averaging 700 mrem) in concluding that the addition of
350 mrem of exposure resulting from Yucca Mountain to natural background radiation in
the vicinity of Yucca Mountain is acceptable because the total exposure is similar to natural
background radiation in other areas of the United States (i .e. Colorado). Use of Colorado
levels of natural background levels of radiation might be appropriate if the Yucca Mountain
project were being proposed in Colorado. In reality, persons living in the vicinity of Yucca
Mountain might be exposed to twice the level of natural background radiation. EPA
suggests that this level of exposure (700 mrem) is an acceptable risk because natural
background radiation in Colorado is 700 mrem. If this argument is valid, then could one
conclude that if the repository were located in Colorado, the EPA standard could be set at
700 mrem and the acceptable level of exposure risk would be 1,400 mrem? In lieu of the
350 mrem standard between years 10,001 and 1,000,000, EPA should consider the Yucca
Mountain repository as being allowed to only contribute an incremental increase in
exposure risk which is consistent with the variation in natural background radiation in the
vicinity of Yucca Mountain. Pages 100 and 101 of EPA's proposed rule place said variation
at 70 to 100 mrem. A standard allowing Yucca Mountain to contribute not more than 70 to
100 mrem would result in Yucca Mountain related exposure levels not exceeding the
variation in natural background radiation in the vicinity of the project. (Comment 0315-3)
8.	EPA's use of Colorado's higher level of "background radiation" in an attempt to justify
allowing added doses of 350 mrem/yr to persons living downstream from Yucca's, leaking
radioactive wastes is twisted and unacceptable. EPA cites the national average for
background radiation as 350 mrem/yr. But even this is wrong and misleading. About two
thirds of that figure is due to radon exposures within houses and buildings. Only natural
radiation, such as from cosmic rays and other natural sources that people are exposed to
outdoors, which is difficult to avoid or control, should be considered "natural background."
EPA's proposed. 350 mrem/yr dose from Yucca's leaking radioactive wastes would be in
addition to the background radiation (including indoor radon) that people would already be
exposed to. It should be noted that residents near Yucca are also exposed to additional
radioactive contamination from the nearby Nevada Test Site's nuclear weapons explosions
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and "low" level radioactive waste shipments and dumping, nuclear rocket and other
radioactive experiments at the Nevada Test Site, as well as additional "low" level
radioactive waste dumping at a commercial facility in Beatty,
Nevada. In NAS's recent BEIR VII study, it reported that about 1 in 100 Americans will
contract cancer just from the non-radon component of background radiation. A full three
percent of the American public can already be expected to contract cancer from their
exposure to outdoor natural radiation plus indoor radon, so that a "background radiation"
dose of 350 mrem/yr is far from safe. (Comment 0324-8)
9.	Amargosa Valley residents now mostly live in mobile homes. As a consequence they
have low indoor radon doses. Colorado residents have better insulated houses and so have
higher indoor radon doses. This makes for a higher Amargosa Valley-Colorado difference,
and therefore under EPA's theory a higher Yucca mountain dose standard than might
otherwise be the case. Are future Amargosa Valley residents to be punished simply because
current residents cannot afford well -insulated houses? Should we assume the status of
Amargosa Valley residents will improve in the near future and their indoor radon doses
will increase? Similarly, EPA is encouraging indoor radon abatement in Colorado.
Congress has set a national goal to reduce indoor radon levels to those outdoors. Should we
assume some of this will have been successful? Both assumptions together could reduce the
Amargosa Valley-Colorado difference to a small number, even to zero. In pursuing the
Amargosa Valley-Colorado radiation dose comparison, EPA is not basing its health
standard on sound science but on quicksand. (Comments 0357-2 and 359-2)
10.	But 350 millirem as a background reference is wrong. It includes indoor radon, ... it is
wrong to include indoor radon as background because indoor radon is an artifact of
construction. It's like taking a natural sample of lake water, boiling it, and then saying that
the resultant salt concentrations are natural concentrations. This is conceptually a very
wrong way of characterizing background. Natural background is about 100 millirem with
some variations in altitude due to cosmic rays and sun variations .... But the proper way to
characterize radon in natural background is outdoor radon, not indoor radon. I have given
you a very specific analogy and I expect that in the comments that EPA will respond to this
analogy. I do think that the proper reference point is not even the 100 millirem natural
background, but the small variations in cosmic rays or internal radiation that we might get
when we move from one place to another. That's a good reference. Twenty-five millirem
comes from approximately there. It's a good way to proceed if there is a drinking water
sublimit. (Comments 0368.3-3, 0368.3-4, and 0368.4-1)
11.	Second, by including radon exposure as part of the natural background radiation, EPA
is dishonestly inflating background levels. Radon is normally never included as part of
background dose because indoor radon exposure is a man-made public health risk. EPA
itself has classified radon as a known human carcinogen. (Comment 0368.6-10)
12.	... in establishing the standard for natural background radiation levels, the EPA
blatantly includes exposure to indoor radon which is a man-made product and not a part of
natural background. (Comment 0368.10-4)
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Response to Issue C:
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule. Notwithstanding, we should note that we disagree with the basic
conclusions of the commenters. The terminology "natural radiation" routinely includes
consideration of radiation doses from indoor radon exposures. As we stated in the preamble
to the proposal (70 FR 49037), background radiation is the radiation that humans receive
from the natural sources of radiation in the environment. The emphasis we wish to
highlight here is natural sources. This dose consists of external exposures from cosmic and
terrestrial sources, and internal exposures from naturally occurring radon. These sources
consist principally of cosmic rays entering the earth's atmosphere; gamma rays largely
from uranium and thorium, including their decay products, found in various concentrations
throughout the Earth's crust; potassium-40, a radioisotope which is mixed in small
concentrations in nature with stable potassium; and radon decay products. Through natural
background radiation, people are exposed to external radiation and internal radiation by
inhalation and ingestion of radioactive substances in the natural environment (NEA Issue
Brief, http://vvvvvv.nea.fr/html/brief/brief-10.html).
Radon is a naturally occurring gaseous element that is commonly included in definitions of
natural background ((NCRP Report 94, Exposure of the Population of the United States
and Canada From Natural Background Radiation,
http://vvvvvv.ncrponline.oru/Publications/94press.html. IAEA Fact Sheet,
http://www.iaea.org/Publications/Factsheets/English/radlife.html: UNSCEAR, Sources and
Effects of Ionizing Radiation, 2000, Annex B, p. 89;
(http://vvvvvv.unscear.org/unscear/en/publications/2000 1 .html): Background as a Residual
Radioactivity Criterion for Decommissioning, US Nuclear Regulatory Commission,
NlJREG-1501, 1994 ( http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/srl501/
)). In fact, the widely cited figure of 300 mrem/yr as the average natural dose rate in the
United States includes radon (NCRP 94). Nor do we agree with the commenter 0314.1-13
that ICRP excluded radon from its public dose limit because it did not view radon as a
component of natural background radiation. There can be tremendous fluctuation in the
overall dose people receive based on several determinants, namely altitude and geology,
but by far the largest portion of the dose received is from radon and as such, we believe
(along with most national and international radiation experts, see above) that radon should
be included in any assessment of natural background radiation. In homes and buildings,
there are radioactive elements in the air. These radioactive elements include radon, and by-
products formed by the decay of radium (radium-226) and thorium present in many sorts of
rocks, building materials, and in the soil.
There is a distinction between sources of radon to which people are exposed, and this may
possibly lead to the confusion over whether radon is a "construction artifact." The two
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main sources of radon are from technologically enhanced naturally occurring radioactive
material, or TENORM, that is in radium-bearing construction or fill materials from which
radon and its progeny escape into a closed space, and undisturbed radium-bearing rock or
soil. An example of exposure from TENORM is from radon or its progeny inhaled by
people exposed to certain types of wallboard or fertilizers produced with phosphogypsum
that contains radium. These types of exposures were not included in our definition of
background radiation because they are artifacts of the construction of the wallboard, or
exposure to a technologically enhanced product such as fertilizer, and it is difficult, if not
impossible, to determine average rates of exposure from TENORM. We do include,
however, radon exposure resulting from undisturbed radium-bearing rock or soil beneath or
near buildings ("Assessment of Variations in Radiation Exposure in the United States,"
Docket No. EPA-HQ-OAR-2005-0083-0077, updated for the final rule at Docket No. EPA-
HQ-OAR-2005-0083-0387, p. 2). This is a naturally occurring exposure that is a major
contributor to the annual dose we all receive. Commenters who refer to this exposure as
"man-made" (e.g., Comments 0293-11, 0368.6-10, and 0368.10-4) are incorrect. However,
we recognize that indoor radon concentrations, and resulting exposures, are influenced by
the type of dwelling (as noted in Issues D and G of this section, the use of mobile homes by
residents of Amargosa Valley may significantly affect their radon exposures).
As described earlier, radon exposures can vary widely even in localized areas for a number
of reasons. While average doses from radon are widely cited to be roughly 200 mrem/yr,
based on the correlation with a concentration of 1 pCi/L (see NCRP 94), measurements
indicate that some exposures could be more than ten times that level in unique situations.
The concentration at which EPA recommends action be taken to mitigate exposures is 4
picocuries per liter (pCi/L). The Agency further recommends that homeowners consider
taking action only if the measured concentration is above 2 pCi/L ("A Citizen's Guide to
Radon: The Guide to Protecting Yourself and Your Family from Radon," EPA 402-K-02-
006, May 2004, Docket No. OAR-2005- 0083-0058). (As an aside, the Citizen's Guide
was written in response to the direction EPA received in the Toxic Substances Control Act
(TSCA), 15 USC 53, 2663. Comment 0314.1-3 mentioned that TSCA recognizes that
indoor radon is an artifact of building construction. That is not entirely correct. The Act
mentions construction types and materials, geology, weather and other variables that may
affect radon levels in new buildings.) It should be understood that EPA's recommendation
of an action level is not based solely on risk, but considers factors such as the voluntary
nature of the exposure, the application to private property, and the capabilities of mitigation
technology. As a result, we also disagree with commenter 0341.1-3 that universal
mitigation should be assumed. EPA's radon abatement program is voluntary rather than a
regulatory requirement. The action level represents a decision point related to technological
achievability rather than health risk. Because of the voluntary nature of the program, EPA
cannot make assumptions regarding how much remediation may or may not occur in the
future.
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Section 3 Background Radiation
Issue D: The background radiation dose rate in Amargosa Valley
1.	We here at Amargosa have been measured at 110 mR in our state, and 15 mR compared
to 110 mR is insignificant compared to the other risks we accept or take. We've worked a
number of years to establish the background in this area, and when people worry
(unintelligible) parked in all these (unintelligible) stations, (unintelligible) our station is
measured at 110 and it's consistent. But I don't mean any point other than this: we should
use, measure and establish background characterization in this community at 110 per year
and that added to 15 mR. A good background (unintelligible) site characterization....
(Comment 0364.2-1)
2.	Why wasn't local data on radon levels used? (Comment 0367.1-8)
3.	Record of 110 millirems/year in Amargosa (plus radon 200 millirems). (Comment
0367.1-14)
4.	We are far below the national average. (Comment 0367.1-15)
5.	Need to get a real number for background in Amargosa. (Comment 0357.1-19)
Response to Issue D:
We accept the commenters' data stating that 110 mrem/yr is a reasonable value to use for
the unshielded, cosmic and terrestrial background radiation dose rate in Amargosa Valley
since it is based upon monitoring data rather than assumptions regarding generalized
regional rates. In light of public comments, we have modified our approach and adopted a
1 mSv (100 mrem)/yr standard for the period between 10,000 and 1 million years. We
believe this standard is protective of public health and adequately addresses our concerns
regarding the increased uncertainty in long-term performance projections.
Section 3 Background Radiation
Issue E: Other background radiation-related comments
1.	Many articles I've seen on this subject are deliberately misleading the public by stating
that the limit for releases from Yucca is stepping up from 15 mr/yr to 350 mr/yr at the
10,000-year point, conveniently ignoring the fact that the 350 mr/yr limit includes existing
background sources. Perhaps EPA should clarify this point in press releases so the public
can have the truth, or at least the media's deception will be outed. (Comment 0187-2)
2.	Vague references have been made regarding radiation levels in other states. Only
Colorado has been named. (Comment 0209.3-2)
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3.	EPA's new methodology really shows that you spend a lot of time with the Department
of Energy. I have a handout that I recently picked up when I was over at the DOE's office,
and it's their fact sheet on the American's average exposure. And it almost is word for word
for what we keep hearing from Betsy at these roundtables. They're talking about the
radiation exposure coming out of the repository and then adding to background.
And to put this dose in perspective, 660 millirem, which is what they come up with
when they add the releases from Yucca Mountain to the background, is somewhat higher
than the 360 and the national average on a yearly basis. But it's well below levels received
by people living in other parts of the United States. And you're just constantly saying that.
So it appears that you're seeing off the same sheet that the Department of Energy
did, or you certainly had some help with this thing. (Comment 0209.14-2)
4.	Is it possible that we have a higher background here in Nevada because of the Test Site?
(Comment 0210.6-1)
5.	We do not understand what scientific rational that EPA is using in comparing natural
background radiation to potential radiation exposures from YMP in setting the YMP
radiation standard. There are scientifically significant differences between potential YMP
radiation exposure and natural background exposure including the drinking exposure mode;
the composition of radionuclides and energy levels; tissue deposition of radionuclides, and
cancer risk. The important YMP health risk is posed by ingestion in contrast to
background radiation where the principle concern is external radiation. Finally, the EPA
justifies the new radiation exposure standards based on the radiation absorbed during
routine x-rays. This analogy is misleading due to differences in the manner that one
receives the radiation dose. (Comment 0214-3)
6.	While the concept of matching "background" radiation seems benign, it should be noted
that the 350 millirem limit is for a maximum exposure nationwide. Even at Yucca Mt., next
to the Nuclear Weapons Test Site, annual background exposure is about 110. Furthermore,
background radiation causes serious cancers each year, skin cancers, melanomas and more,
especially in this sunny desert region. (Comment 0306-9)
7.	The proposed rule prescribes a dose limit to be used beyond 10,000 years that is based
on current average annual background radiation levels in Amargosa Valley, Nevada, and in
Colorado. If those background values are higher now, or in 2000, say, than they were in
1900, because of Hiroshima, Nagasaki, atmospheric nuclear weapons testing, Chernobyl,
ongoing reactor plant operation, etc., then would it not be appropriate to extrapolate those
increases; i.e., to accumulate the century-on-century increases in average annual
background radiation in Amargosa Valley and Colorado out to 10,000 years and beyond?
Would using those larger extrapolated values not be more consistent with the "comparison
with background radiation levels" rationale that undergirds the new 350 mrem/year limit?
Indeed, the extrapolation should perhaps not be a linear one, given (based only on my
cursory survey of the past 10,000 years) (Comment 0307-1)
8.	We believe that it is misleading to make a comparison between natural background
radiation and that which comes from nuclear waste. (Comment 0341-7)
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9.	What effect does the old NRDS project have on levels today? (Comment 0367.1-10)
10.	NRDS has been included in background. (Comment 0367.1-23)
11.	How can EPA know what background radiation levels will be like in 10,000 years?
(Comment 0367.2-24)
Response to Issue E:
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule.
Comment 0187 suggested that we clarify the dose standards that DOE will be required to
meet from the time of repository closure out to 10,000 years, and from 10,001 years to 1
million years. These standards, respectively, are 15 mrem/yr, and 100 mrem/yr in addition
to background radiation. Our rationale behind the setting of these limits can be found in the
Dose Limits section of this document (Section 2).
Commenter 0306-9 stated that background radiation causes serious cancers each year, skin
cancers, melanomas and more, especially in a sunny desert region like Yucca Mountain.
As we discussed in our proposal, background radiation can be highly variable. We would
point out that the commenter refers specifically to skin cancers, for which sun exposure is
the leading cause. Sun damage is caused primarily by radiation in the ultraviolet portion of
the spectrum, and while the higher-energy portion of the ultraviolet range can be ionizing
(sufficient energy to break chemical bonds and remove electrons), it is significantly lower
in energy than the gamma radiation typically included in "background radiation." See
http ://www. epa. gov/ sunwise/.
Comment 0214 stated that we justified our radiation standard based on the radiation
absorbed by routine x-rays. That is incorrect. We justified the 15 mrem/yr standard within
10,000 years as consistent with EPA's risk management policies, representing a lifetime
risk of roughly 3 x 10"4 (given a 30-year exposure period). As the commenter points out,
the factor used to convert dose to risk is based on external radiation (but not x-rays). Risks
from internal exposures could be slightly higher or lower, depending on the radionuclide.
However, we find that this conversion provides a reasonable estimate of overall risk when
multiple radionuclides and exposure pathways are involved in projecting doses over long
time periods.
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Commenters 0210.6-1 and 0367.1 questioned whether there could be higher background
radiation levels because of either the Nevada Test Site or the Nuclear Rocket Development
Station (NRDS). We are not aware that radiation levels in the Yucca Mountain or
Amargosa Valley areas are significantly higher because of the Test Site and NRDS
activities.
Section 3 Background Radiation
Issue F: Comparison with radiotoxicitv of ore
1.	Other questions would include, how can one defend any conclusion that Yucca would be
"unacceptable" hundreds of thousands of years from now when the radioactivity (and
radiotoxicity) level of the waste is already more than an order of magnitude less than the
uranium ore that was originally dug up to make it? After the waste has become less
radioactive than the original ore, all obligations should end. At that point, the only
difference between the waste and the ore is that it is less radioactive, and that it is far more
isolated from humanity than the ore would have been (as the ore has no man-made
confinement, and is randomly distributed all over the place, in contact with ground water,
etc...). (Comment 0201-8)
2.	In fact, only one thing about the next million years is known for certain - that during this
time, the hazard of used nuclear fuel will become less than that of the natural uranium from
which it was produced. This does not mean to imply that we would support a standard
setting a compliance period extending to the time at which the radiotoxicity of used fuel
becomes less than that of uranium ore. As EPA has correctly pointed out in its proposal,
there is a general lack of agreement in the scientific community on the practicality and
appropriateness of this measure. Calculations differ, based on assumptions, as to the point
at which the radiotoxicity of the fuel equals that of the uranium ore from which it was
produced. However, this point is generally believed to fall somewhere between 10,000 and
300,000 years. This measure, while not useful in establishing a regulatory compliance
period, does provide a figure of merit for comparing the relative significance of the
hypothetical hazard from which EPA is proposing to protect the next 25,000 generations -
demonstrating that, for most if not all of the period beyond 10,000 years, the hazard is
comparable to naturally occurring hazards and is continually becoming even less
significant over time. (Comment 0298-4)
3.	EPA's proposed 350 mrem/yr dose would not just occur for a brief time and then
decrease to far lower levels. Under EPA's proposal, these large doses would be permitted to
occur year after year, generation after generation, forevermore into the future (well, out to a
million years, after which time regulations would end, although certain radionuclides
would remain hazardous and deadly even much further into the future than that). Under
EPA's proposal — given the lack of a cap on maximum doses and the hundreds of
thousands of years these leaking wastes would remain harmful - significant numbers of the
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people most exposed to radiation doses could suffer a statistical 100% risk of contracting
cancer. The State of Nevada has noted that EPA, on page 108 of the proposed rule, holds
that exposures of the magnitude associated with un-mined uranium ore bodies meet the
standard of "minimal justice." EPA further states that estimates of the risks from un-mined
ore bodies range upward to 100,000 excess cancer deaths over 10,000 years, So it follows
that EPA believes ten excess deaths per year are acceptable For a 1,000,000 year
assessment period called for by the proposed Yucca rule, this means that ten million
excess deaths would be acceptable to EPA. Ten million excess cancer deaths, however, is
again nightmarishly unacceptable. (Comment 0324-5)
4.	A level of protection at 350 mrem/yr also is supported by a comparison of that level of
protection with the effects of existing uranium ore bodies. In setting the release standard in
Part 191, EPA evaluated the health risks to future populations from the ore needed to
produce 100,000 metric tons of reactor fuel, if the ore had not been mined to begin with,
and concluded that the population risks ranged between 10 and 100,000 premature cancer
deaths over 10,000 years. The acceptability of the release standard was supported by the
observation that "...leaving the ore unmined appears to present a risk to future generations
comparable to the risks from disposal of wastes covered by these standards." (Comment
0352-26)
5.	Additional emphasis on ore body comparison as a fundamental rationale for the
acceptability of the proposed dose limit, however, would strengthen the rationale for
selection of the proposed level of protection, both through consistency with the philosophy
of protection in Part 191, and as an additional independent rationale for the proposed limit.
Background radiation gives a perspective on the significance of the risk in terms of other
omnipresent radiation risks that are routinely accepted. The ore body comparison provides
an ethical argument as well; this generation should not be expected to improve upon the
situation that would have resulted if the ore had not been mined in the first place, as would
be the case in the very long run after the engineered features have done their job and the
repository looks much like an ore body. (Comment 0352-27)
6.	The idea of using the original unmined ore body as a basis for comparison in regulating
high-level radioactive waste disposal in the United States was suggested in the early days
of development of EPA regulations by the Natural Resources Defense Council, in a paper
on radioactive waste management prepared for the Department of Energy. That paper
recommended a principle of strict neutrality with respect to imposition of risks on the
future, i.e., there should be no net increase in risks imposed on future generations by the
use of nuclear power, independent of any consideration of the benefits this generation
might achieve from such use. The report concluded that this policy toward the future would
be the most fair way to proceed and stated that "This policy's practical embodiment is a
disposal system producing no more risks to the future than would have been produced by
original uranium ore bodies utilized in nuclear power, assuming they had remained
unmined." One can disagree with the ethical argument that a policy of strict neutrality
toward the future-considering only risks, ignoring benefits-is obligatory. However, even
holding to this strict principle leads to a comparison with the original ore body, not to an
abstract standard of safety. (Comment 0352-28)
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7.	Another report prepared for the Department in 1980 looked at comparisons of releases
from a potential repository to the unmined uranium ore deposits from which the fuel was
originally taken and presents calculations for individual doses for actual ore bodies, using
various water consumption scenarios, including a well within one mile of the ore body. The
report presents a comparison of reasonable ranges of performance for reference repositories
to doses associated with numerous ore bodies. The report calculates annual doses
significantly above 100 rem for several ore bodies. Furthermore, the 350 mrem/yr level
proposed by EPA is just under half the median and geometric mean of the annual doses
estimated from actual measurements of radium-226 in water at 14 locations associated with
ore bodies analyzed in that report. In comparison, EPA noted that the predicted effects of
the release standard in Part 191 (1,000 statistical deaths in 10,000 years) were at the
midpoint of the range of ore bodies analyzed. Since that range was 1,000 deaths to 100,000
deaths, EPA was clearly using a midpoint in the sense of median or geometric mean, rather
than the arithmetic mean. (Comment 0352-29)
8.	In summary, comparison of the repository to existing ore bodies is relevant to
establishing a peak dose standard from two perspectives. First, from the technical
perspective, it has not been shown that a geologic repository can reasonably be expected to
perform much better than a uranium ore body at a time in the distant future when the
engineered barriers have deteriorated and the repository looks very much like an ore body.
Second, from an ethical perspective, it has not been shown why a repository should be
expected to do so. (Comment 0352-30)
9.	The release limit in Part 191 was not mathematically derived from the analyses of ore
bodies or of conceptual repositories. Rather, it was determined to be a level that was
achievable and that was clearly acceptable in view of those analyses. Using the same
approach for the peak dose standard, EPA should emphasize that the comparisons with ore
bodies and background radiation levels are just that, comparisons, rather than the basis for
a rigorous mathematical derivation of the 350 mrem/yr limit. The Department believes this
interpretation is consistent both with the logic used in establishing Part 191 and with EPA's
acknowledgement that the proposed level of 3 50 mrem/yr "... will limit total radiation
exposures of the RMEI to levels comparable to those incurred today from natural sources
by residents of a nearby western State (emphasis added)." The phrase comparable to
implies a looser relationship than strict equality. Translation of this objective into a
quantitative rule should be informed, but not dictated, by use of a specific example or
examples, such as the comparison between Amargosa Valley and Colorado. In other
words, EPA should make it clear that the basis of the 350 mrem/yr standard follows from
comparisons with both unmined ore bodies and incremental doses that would be incurred
by moving from Amargosa Valley to another area with a higher level of background
radiation, in the sense that it is in the range of estimates of such doses and for that reason is
judged to be acceptable. This logic would be fully compatible with the reasoning
supporting the performance standards that apply to other geologic repositories. (Comment
0352-31)
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Response to Issue F:
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule.
Although the comparison of the repository to a natural ore body is no longer relevant, we
briefly address the comments on this topic.
We agree with comments that, over periods up to 1 million years, the hazard of used
nuclear fuel becomes less than that of the natural uranium from which it was produced. In
fact, we discussed the concept at length in the preamble to our proposal (70 FR 49039).
We also agree with Commenter 0352-31 who states that the release limits for 40 CFR part
191 were not derived from the analyses of ore bodies, and that comparisons with ore bodies
and background radiation levels were not the basis for a rigorous mathematical derivation
of the originally proposed 350 mrem/yr limit.
Comment 0324-5 is correct that a peak dose rate may continue for more than one year.
However, the commenter infers that the peak dose would last forever, and states that there
would be a "lack of cap on the maximum dose," inferring that the peak dose would increase
as time went by, and that is incorrect. The maximum allowable dose for the purposes of
compliance, represented by the mean of the distribution of the projected doses, is 1 mSv/yr
(100 mrem/yr). We have not, however, required that compliance be assessed against the
"worst case" projected dose, if that is what the commenter means.
As Comment 0352-29 noted, the release limits in 40 CFR part 191 were scaled to a level
estimated to result in 1,000 fatal cancers over 10,000 years from disposal of 100,000 metric
tons of heavy metal (the midpoint of a range estimated between 10 and 100,000 excess
fatalities). Thus, Commenter 0298 is incorrect in implying that the high end of the
estimated range of risks from uranium ore represents the level upon which the 350 mrem/yr
individual peak dose standard is based.
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Section 3 Background Radiation
Issue G: Dade Moeller report
1.	A recent calculation by an internationally renowned health physicist, using information
on estimating effective dose rates from radon that is more recent than that used by EPA and
data specific to Amargosa Valley, Nevada... was able to gather the necessary site-specific
data and compare background levels in Amargosa Valley to a specific location in Colorado
(Leadville). Using location-specific data for Amargosa Valley and Leadville, the
calculations.. .indicate a difference in background radiation of 410 mrem/yr with the new
equivalency factors. This information provides additional support for the conclusion that
EPA's proposed level for individual protection at time of peak dose of 350 mrem/yr is
reasonable. (Comment 0352-20)
2.	The initial purpose of this [Dade Moeller] review was to compare the estimated total
effective dose rate to residents of the Amargosa Valley, NV, due to exposures to naturally
occurring radiation sources, to that of a comparable group that was known to have a
relatively high dose rate from these same sources... Such an approach would be in accord
with a long-standing recommendation of the International Commission on Radiological
Protection, namely, that differences in natural background dose rates can serve as a useful
basis for the establishment of dose rates that would be acceptable for members of the public
on a long-term basis. (Comment 0352-42)
3.	In its Proposed Rule, the USEPA stated that, in making such assessments, it was their
intention to limit the sources to "external exposures from cosmic and terrestrial sources,
and internal exposures to naturally-occurring radon." This, however, left open the question
of whether only indoor exposures, outdoor exposures, or a combination of the two, would
be considered. The contractor hired by the USEPA prepared a report in which they
addressed indoor exposures only. In addition, rather than comparing the dose rates in two
communities, they compared average dose rate estimates for the States of Nevada and
Colorado. (Comment 0352-43)
4.	[SJurveys show that about 91 percent of the Amargosa Valley residents live in mobile
homes. According to staff members in the Florida and North Carolina State Radiation
Control Programs, and the USEPA, the average indoor radon concentration, for this
population group, will be essentially the same as that outdoors. The reason is that mobile
homes are typically placed on supports such that the floor is a foot or more above the
ground. For this reason, there is a relatively small [if any] pressure gradient to "force" the
radon, released from the ground, to move into the home. In addition, the supporting
structures for such homes include several layers of plywood, that are covered by floors that,
not only have no open cracks or joints but also are, in turn, supported by a steel box frame
enclosed within an impervious outer steel sheet metal container. (Comment 0352-44)
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5. EPA chose a key conversion rate from radon concentration (actually, the concentration
of radon daughter products) to lung irradiation that is substantially different from the one
chosen by an NCRP expert committee. Dr. Moeller is a recognized authority on the subject
and he reported that the NCRP committee dealing with these standards had changed that
key factor by a factor of two, and that EPA had relied on the older figure. Using the correct
conversion factor generally reduces radon dose estimates by a factor of two. Moreover, Dr.
Moeller points out that it had been widely known for some time that the previous number
was not used by the standard international reference; EPA gave no recognition of this in its
key background report and in using that report to concoct its dose standard for Amargosa
Valley. That EPA made such a skewed choice for the key conversion factor when it knew
or should have known better undermines the credibility of its technical backup generally.
(Comments 0357-1 and 0359-1)
Response to Issue G:
The comments refer to an article in the October 2006 edition of Health Physics by Dr.
Dade Moeller ("Comparison of Natural Background Dose Rates for Residents of the
Amargosa Valley, NV, to Those in Leadville, CO, and the States of Colorado and Nevada,"
co-authored by Lin-Shen Sun). Dr. Moeller is a well-known health physicist and past chair
of the Health Physics Society. Dr. Moeller also presented his results at a public meeting of
the NRC's Advisory Committee on Nuclear Waste (ACNW) in November 2005 (Docket
No. EPA-HQ-OAR-2005-0083-0376), and a preliminary version of his paper was
submitted with public comments by the Department of Energy (Docket No. EPA-HQ-
OAR-2005-0083-0352).
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule. In addition to the comments we received that supported the use of natural
background in setting a dose standard, we also received a significant number of comments
taking issue with the concept of using background radiation as an indicator of "safe" levels
of exposure from an engineered facility. We also received additional information that
provided insights into our consideration of background radiation. For example, monitoring
stations operated by the Desert Research Institute provided monitoring data indicating that
the unshielded (outdoor) background radiation from cosmic and terrestrial sources in
Amargosa Valley is roughly 110 mrem/yr. Commenters 0357 and 0359 also informed us
that roughly 90% of the population in Amargosa Valley lives in mobile homes, which has
implications for indoor radon exposures. Other commenters supported the use of a
different factor for converting radon concentrations into dose.
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In considering these comments, as well as those taking issue with the overall premise
described in the proposal, we found the relatively simple approach used in the proposal
evolving into a more complex undertaking requiring numerous decisions where science did
not provide a clear answer. Indoor radon estimates presented the greatest challenge, and
also represented the highest proportion of overall background radiation. Complicating
factors included multiple ways of calculating radon dose, the prevalence of mobile homes
in Amargosa Valley, limited data sets primarily from the early 1990s, and data for
individual counties in a different format than state-wide data. We concluded that there was
no generally agreed-upon approach in the context of Amargosa Valley for incorporating
indoor radon exposures into an analysis of background radiation. As a result, we
determined that we could not satisfactorily derive a standard from such an analysis,
particularly given the fact that many commenters viewed the entire concept as arbitrary.
We continue to believe that references to natural sources of radiation can provide useful
insights into the "significance of' projected doses (in IAEA's words) over hundreds of
thousands of years. For example, as noted above, 100 mrem/yr is roughly the value
reported by the Desert Research Institute for cosmic and terrestrial radiation at Amargosa
Valley (unshielded). When shielding from buildings is considered and indoor radon doses
are estimated using a more conservative conversion factor suggested by some commenters,
100 mrem/yr is at the low end of overall background radiation estimates in Amargosa
Valley and nationally. Within the State of Nevada, the difference in average estimates of
background radiation for counties is greater than 100 mrem/yr. (Docket No. EPA-HQ-
OAR-2005-0083-0387) This suggests that 100 mrem/yr can be considered to be a level
such that the total potential doses incurred by the RMEI from the combination of
background radiation and releases from Yucca Mountain will remain below doses incurred
by residents of other parts of the country from natural sources alone. It may also be noted
that the 1 mSv/yr (100 mrem/yr) public dose limit recommended by ICRP is itself related
to background radiation. (ICRP Publication 60, Docket No. EPA-HQ-OAR-2005-0083-
0421, paragraphs 190 and 191) However, in the absence of compelling reasons for
selecting specific background radiation estimates and points of comparison, we conclude
that comparing background radiation estimates from specific locations does not provide a
clear or sufficient basis for a regulatory compliance standard applicable to the Yucca
Mountain disposal system.
Dr. Moeller also employed a radon dose conversion factor lower than ours, which he cites
as consistent with UNSCEAR and forthcoming NCRP recommendations. The factor we
employed for our proposal is that published by NCRP in its initial studies of background
radiation in Publications 93 and 94. Much work has been done in this area, but there is no
consensus that the earlier factors are outdated. Nevertheless, we have revised the
background radiation elements in our supporting technical document using the conversion
factor suggested by Dr. Moeller. Readers can judge for themselves the significance of this
factor in deriving such estimates.
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Section 3 Background Radiation
Issue H: Why Colorado?
1.	Discerning how the Colorado rationale is actually supposed to justify EPA's proposed
standard is not easy, for EPA's explanation of the rationale is far from clear. EPA never
performs any kind of risk assessment that concludes that a 700 millirem total exposure is
safe. Nor does it ever suggest that the fact that people's choices to live in Colorado reflect a
societal judgment that such exposure levels are safe; EPA specifically states that" [i]t
should be clear that we are not arguing that most people take into account levels of
background radiation when deciding where to live or work, or that it in any way plays a
major role in their decision-making." 70 FR 49038. Instead, EPA reasons that since levels
of exposure near 700 millirem/year occur naturally in a few isolated places, and people live
in those areas without obviously dying in droves, a standard that allows 350 millirem/year
anthropogenic exposures on top of the already occurring 350 millirem/year of natural
exposures in the Amargosa Valley must suffice. As EPA puts it, risk levels apparently are
fine so long as "in EPA's view" those levels "do not 'pose a realistic threat of irreversible
harm or catastrophic consequences.'" Id. EPA does not explain why it holds this view. But
the rationale is in any event arbitrary. EPA's role is to establish a standard protective of
public health and safety and never in the past has it considered that role to be fulfilled
merely through avoidance of "a realistic threat of irreversible harm or catastrophic
consequences." Instead, it has set standards, both to protect people from radiation and in
other regulatory contexts, designed to allow only the most minimal of increases in the
levels of cancer and other illnesses already induced by background levels of radiation.
(Comment 0226-52)
2.	Independently of these errors, EPA's method of choosing its natural background
benchmark is irrational. If EPA were to utilize a natural background standard, the most
logical benchmark for that standard would be natural levels in the Yucca Mountain area or,
perhaps, in the nation as a whole, which has average radiation levels significantly lower
than those that already exist in the Amargosa Valley. But EPA has deliberately rejected
both possibilities, and has chosen Colorado for two simple reasons: first, because Colorado
has substantially higher natural background radiation than the Amargosa Valley or the
country as a whole; and second, because Colorado also is in the western United States.
(Comment 0226-57)
3.	EPA's reliance on the former reason is completely circular. In effect, EPA has
determined that increased radiation is appropriate by comparing conditions in the
Amargosa Valley to a subset of other states, all of which it selected specifically because
they have higher exposure levels, and within that subset has chosen Colorado over Idaho
apparently just because Colorado is more radioactive. EPA thus based its conclusion that
higher exposure levels are allowable on the premise that its analysis must produce a
conclusion that higher exposure levels are allowable. Put differently, EPA has proposed
that Nevada can have substantially higher exposure levels because Colorado does, and has
said that Colorado is an appropriate comparison because it has substantially higher
exposure levels. This reasoning lacks any logic. Comparing Nevada to Colorado because
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both are in the West, and therefore determining that Colorado's natural background levels
are appropriate for Nevada, is as reasonable as suggesting that humans could appropriately
recreate New Orleans' flood risk in Atlanta because both are in the South. EPA has
provided no other reason for its selection of Colorado. That selection therefore appears to
represent an obvious effort by EPA to rig its analysis, and to justify its predetermined
conclusion that an unprecedented high standard should be employed. As the report by Dr.
Fleming in Appendix D establishes, EPA cannot assume that natural background or
variations in natural background are acceptable risks. Yet this appears to the basis for
EPA's proposal. (Comment 0226-58)
4.	The adoption of the so-called "Colorado standard" demonstrates the depths of
rationalization and self justification that's been employed to weasel out from the intent of
the NAS and Circuit Court of Appeals decisions. (Comment 0309-4)
5.	The rule's explanation does not adequately explain why Colorado was chosen. The
figures for background radiation for Amargosa Valley are not clearly documented. EPA is
being arbitrary in choosing the background radiation for Colorado. It is our understanding
that radon is a major contributing factor to that background radiation and thus is not similar
to the Amargosa environment. In addition, just because a risk exists naturally in one
location does not mean that it is acceptable or "safe" for humans to create it somewhere
else. Why choose the background radiation level for the area that will not be directly
affected? Wouldn't it be more appropriate to use background radiation level for Nevada or
for the nation as a whole? It appears to us that when it is to the advantage of the
government to use site-specific standards, they are promulgated. But when site specific
numbers are problematic for the repository to meet standards, then the government opts for
generic standards. (Comments 0353-4 and 0361-4)
6.	Why does EPA use Colorado as a comparison? (Comment 0367.2-6)
Response to Issue H:
After considering all of the comments that we received on the use of background radiation
to establish the long-term dose limit, we have decided not to adopt the proposed 3.5 mSv/yr
(350 mrem/yr) level as the compliance standard for the period beyond 10,000 years, nor
have we adopted the reasoning used to support the proposed standard (i.e., considerations
of background radiation) in the selection of the 1 mSv/yr (100 mrem/yr) level established
in our final rule. Given the adoption of a standard that is protective of public health and
safety, and the existence of a rational basis therefor, it is not necessary to respond to
comments on the earlier justification for the 350 mrem/yr level, and, in particular, whether
a location in the State of Colorado was an appropriate reference point.
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Section 4 Two-Tiered Standard
Issue A: Oppose use of a two-tiered standard
1. EPA is proposing the least protective radiation standard in the world. No other US or
international radiation protection standard permits a dose of 350 millirems per year to
members of the public. Most other countries proposing a geologic repository have proposed
or established a radiation standard of 10 millirems per year. Swiss regulations explicitly set
no "expiration date" on protecting future generations. Calculations done for Nevada's
Agency for Nuclear Projects demonstrate this standard is "ten times greater than what EPA,
NRC, and other regulatory bodies have previously allowed for all non-medical sources
combined." (Comments 0126-4, 0127-4, 0133-6, 0135-6, 0137-6, 0144-5, 0146-6, 0147-6,
0148-6, 0150-3, 0159-6, 0163-6, 0164-5, 0182-4, 0189-4, 0190-5, 0195-1, 0293-8, and
0302-1 )
2.1 think it is absurd to apply a new definition to maximum safe levels of radiation
exposure in order to justify the dumping of nuclear waste on Nevada. (Comment 0142-1)
3.1 strongly object to the two-tiered standard that jeopardizes the health and safety of the
future residents of Nevada. The EPA proposal would set a horrible precedent and is in
contravention of internationally accepted radiation protection standards, not to mention
basic ethical standards. There is a Native American proverb which the current leadership of
the EPA would do well to contemplate: We do not inherit the earth from our ancestors, we
borrow it from our children. (Comment 0128-1)
4.	Please re-evaluate the radiation double standard and stop committing these terrible
injustices against the people of Nevada, both citizens and the Native Americans.
(Comment 0140-2)
5.	EPA's proposed double standard must be withdrawn. The proposal would protect people
for the first 10,000 years to currently applied standards of protection, but would then doom
future generations after that to a 1 in 36 cancer rate ( or even worse, up to 100% cancer
rate, due to EPA mathematical manipulation), and a 1 in 72 fatal cancer rate (or even
worse). Such proposed cancer rates and fatal cancer rates are horrifying... (Comments
0175-1 and 0177-1)
6.	Instead of 10,000 years, a more appropriate conversion point would be when the
engineered barriers are expected to fail completely and when protection will be afforded on
by the natural barriers. (Comments 0180-1 and 0181-1)
7.	We strongly oppose the new radiation standards that have been proposed for Yucca
Mountain, which call for differing levels of protection—one level for the first 10,000 years,
and then catastrophically reduced standards for all following generations of humans. It is
absolutely essential that you retain the current standards for all future generations.
(Comment 0200-1)
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8.	At the roundtable presentation, vague references have been made to radiation standards
in other countries. Which countries and what levels of radiation? (Comment 0209.3-1)
9.	And I would refer you to 10 CFR, Part 50, Appendix 1, Section 2A: By accepting a false
premise that no man may package relief within the first 10,000 years - and I would submit
that's a complete - that's totally preposterous.
EPA has created a bifurcated standard, which fails to protect the public in the first
10,000 years of the repository's operation. And, unquestionably, in the period beyond the
first 10,000 years, fails at nearly astronomical rates. (Comment 0209.6-5)
10.	EPA's unprecedented proposal - proposed maximum dose for an individual after the
first 10,000 years is 14 times higher than the dose allowed for low-level waste disposal in
the United States currently. It's also ten times higher than the level of protection
recommended by the National Academy, as you've heard earlier, 35 to 100 times more —
less protective than those living near nuclear power plants. (Comment 0209.7-6)
11.	If the Bush Administration is successful, these nuke standards will be the least
protective radiation standards of the world. (Comment 0209.12-8)
12.	Your attempt to bifurcate this radiation standard throws out all attempts at generational
equity and puts future generations at tremendous risk, the very risk that mandated not
happen — Congress mandated not happen. (Comment 0209.13-2)
13.	Use of a two-tiered standard is unstable, and we don't know if it's protective to humans
one million years in the future. (Comment 0210.1-3)
14.	With regard to EPA's proposed multiple-dose standards, Lincoln and White Pine
County believe said standard adequately considers protection of public health. (Comment
0211.1-2)
15.	Concerning the longer-term radiation standard, Lincoln and White Pine Counties are
concerned that the proposed requirement that DOE demonstrate that a person living 11
miles away from the Yucca Mountain site would be exposed to no more than 350 millirem
after 10,000 years of repository operations represents a theoretically arbitrary and
seemingly unjustifiable increase between years 10,000 and 10,001 of repository operations.
(Comments 0211.1-4 and 0315-2)
16.	It is not clear how DOE will be able to demonstrate through performance assessment
that, in the year 10,000, radiation exposure is limited to no more than 15 millirem and then
demonstrate that, in the year 10,001 of operations, the allowable exposure is increased to
350 millirem. EPA is encouraged to give further consideration to the justification for and
public health implications of such a significant one-year increase in allowable exposure.
(Comments 0211.1-5 and 0315-2)
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17.	As it stands, Lincoln and White Pine County residents are left wondering if EPA
believes the 15-millirem standard is required to protect public health and the environment
during the first 10,000 years of repository operation, why would the Agency ever consider
increasing the allowable exposure limit by a factor of 23? (Comment 0211.1-6)
18.	Conversely, if an exposure limit of 350 millirem provides for protection of public
health and the environment in the year 10,001, why would it require a more stringent
standard in prior years? (Comment 0211.1 -7)
19.	According to the group Public Citizen, you are proposing the most harmful radiation
standards that this world has ever seen. As far as the EPA radiation standards goes, this is a
bad thing in general. If we allow standards like this to be approved in our society, we will
eventually perish. It is illogical, immoral, and irresponsible to set standards with such
apathy for these American taxpayers. (Comment 0211.4-2)
20.1 would hope that you guys wouldn't lower the standard. It's dangerous as it is. I did
work at the Test Site 18 years, and you read in the newspaper every day about people that
have been at the Test Site working that's dying. (Comment 0211.6-1)
21.	With regard to EPA's proposed multiple dose standards, Lincoln County believes said
standard adequately considers protection of public health. The near term standard requiring
DOE to demonstrate that a person living 11 miles away from the Yucca Mountain site
would be exposed to no more than 15 millirem of radiation per year during the first 10,000
years of repository operations appears reasonable . Concerning the longer-term radiation
standard, Lincoln County is concerned that the proposed requirement that DOE to
demonstrate that a person living 11 miles away from the Yucca Mountain site would be
exposed to no more than 350 millirem after 10,000 years of repository operations
represents, a theoretically arbitrary and seemingly unjustifiable increase between years
10,000 and 10,001 of repository operations. (Comment 0219-1)
22.	EPA is encouraged to give further consideration to the justification for, and public
health implications of, such a significant one-year increase in allowable exposure. As it
stands, Lincoln County residents are left wondering if EPA believes a 15 millirem standard
is required to protect public health and the environment during the first 10,000 years of
repository operation. Why would the agency ever consider increasing the allowable
exposure limit by a factor of 23. Conversely, if an exposure limit of 350 millirem provides
for protection of public health and the environment in year 10,001, why would it require a
more stringent standard in prior years? The public needs surety that EPA fully understands
the health and environmental consequences of exposure to various levels of radiation.
(Comment 0219-2)
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23.	Standards should not be "degraded" simply because a certain amount of time has
elapsed. If a standard is set for a legitimate reason, it should remain intact until an equally
legitimate reason is found to make an adjustment. The adjustment should be performance
based and not simply because a time limit has passed. A similar concept is the recent
revision of NRC provisions for decay-in-storage for radioactive waste containing
byproduct material. This is a performance based provision rather than simply holding the
materials for a set length of time. EPA should take the same regulatory path and set a
viable, legitimate standard for future generations which can always be reviewed over time.
(Comment 0223-1)
24.	Like its predecessor, EPA's proposed rule would after 10,000 years terminate its only
radiation standard that protects public health. The only innovation in EPA's new approach
is to propose a nominal second-tier standard, 70 times weaker in mean-equivalent terms,
for the longer-term period in which all of DOE's modeling runs show leakage from the
repository. That approach again abrogates the central point of the NAS and the Court: that
the repository should safeguard citizens at the time of the peak dose that will occur from
repository leakage, whenever that occurs. SeeNEI, 373 F.3d at 1273 ("NAS recommended
that the compliance period extend to the time of peak risk") (Emphasis added). Most
importantly, EPA does not and cannot show that its standard will result in a safe geologic
repository at Yucca Mountain... Rather than suggesting any relaxation of the standard after
10,000 years, NAS only qualified the statement by noting that the occurrence needed to be
[wjithin the limits imposed by the long-term geologic environment, which is on the order
of one million years." NAS Report at 2... In short, a rule that terminates the health-
protective standard at 10,000 years despite the absence of any scientific basis, and
thereafter applies a standard dramatically exceeding all established norms for radiation
exposure, using a compliance method that ignores many exposures that are even greater,
cannot possibly qualify as "based upon and consistent with" NAS's peak dose
recommendation. (Comment 0226-1)
25.	EPA's proposed rule never comes to terms with this sharp divergence from its past
practice. EPA insinuates that international bodies support its notion that anthropogenic
sources should be able to double existing natural background levels. But in fact they do not.
EPA's citations are misleading and out of context. See Appendix A. As EPA itself noted,
"[n]o regulatory body that we are aware of considers doses of 150 mrem to be acceptable,"
and those international bodies have never suggested that natural background levels should
create an exception to the more stringent limits they have created. EPA, Response to
Comments at 3-8. (Comment 0226-50)
26.	EPA suggests its rule is "unprecedented" because it was commanded by NAS and the
Court to address time periods after 10,000 years. But that is no rationale. EPA never
explains how a standard that is obviously inadequate can suddenly become adequately
protective at 10,001 years. Nor can it, for EPA has no basis for assuming that human
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susceptibility to radiation will change. Additionally, EPA's suggestion that it need not be
consistent with international precedents, because those precedents do not address long time
frames, is demonstrably false. Many international and national bodies do recommend or
impose regulation over long time frames, and none permits the type of two-orders-of-
magnitude increase in risk that DOE's non-protective second-tier standard would allow.
See Appendix A. (Comment 0226-122)
27.	There is no justification for a two-tiered standard or allowing more risk to future
generations than today's. (Comment 0257-9)
28.	However, in proposing this rule change the EPA has constructed an illogical house of
cards around failed policy based on wishful thinking. The EPA rests its case for a dual
radiation dose standard for near-future and far-future generations on the vast uncertainties
surrounding enterprises projected 10,000 to a million years in the future. (Comment 0267-
1)
29.	The EPA's policy must address the certainties that, given the present design and
location, the containment will fail and harm will occur. The EPA has chosen to address
these certainties not by seeking to avert such disaster—i.e. by forcing the whole enterprise
back to the drawing board—but by pulling a set of numbers out of the (uncertain,
incalculable) future that would justify the currently planned design. These numbers are not
based on science; they are based on hope—hope that the containment will not fail for
hundreds of thousands of years rather than mere thousands or tens of thousands (when
we're using materials that have existed less than a century); hope that humans will not
molest the buried treasure (and assuming their drilling tools are no more penetrating than
our own and they will stop when they hit the treasure chests); hope that the worst geologic
and climatic disasters will not occur (and that pervasive changes will have no effects); hope
that the inevitable exposures are not too harmful; and, above all, hope that the future over
which we have no control will present no surprises we haven't already imagined and taken
into account. (Comment 0267-3)
30.	The assigning of a dual standard thus does not meet the Court directive to comply with
NAS analysis and recommendations. The NAS recommended basing the regulatory
standard on peak exposure. Implicit in that recommendation was the expectation that one
size does fit all when it comes to human beings and radiation exposure. No one should be
exposed to more risk than any of us is willing to bear. And we must count our descendents
as equal members with ourselves of the human race. To do otherwise is to guarantee our
place in future histories as barbarians. (Comment 0267-5)
31.	Environmental Protection Agency is supposed to be an agency to protect the
environment, not protect a polluting industry like the nuke industry. If Yucca can be shown
to be safe; it should be approved. If it can't meet acceptable safety standards, it should be
rejected. But relaxing the standards by orders of magnitude in order to help get an unsafe
project OKd because it can't meet protective standards is immoral. (Comment 0296-8)
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32.	Since.. .the existing 10,000 year standard is sufficiently protective (meeting all four of
NAPA's principles for balancing risks, costs, and benefits fairly across future generations)
and can be developed to address the deficiencies specified by the court in NEI - it should
remain unchanged by this proposal. Any effort to address regulatory compliance beyond
10,000 years must, therefore, be considered as separate and distinct from the existing
standard. It is the nuclear energy industry's belief, supported by international scientific and
regulatory precedent, that the nature of repository safety analysis fundamentally changes
beyond 10,000 years, and that any extension of the regulatory compliance period beyond
this time must recognize this difference. International regulatory bodies have explicitly
recognized the appropriateness of addressing longer time-frames differently, with several
such organizations also recommending a dual track approach similar to that which EPA has
proposed. Most do this by recommending some sort of stylized or generalized and less
detailed approach for longer time periods, such as defining assumptions by regulation
instead of trying to speculatively predict them. (Comment 0298-12)
33.	It is important to note that just because the approach to regulation must, of necessity,
change at 10,000 years, it does not follow that the level of protection is being reduced at
this point. (Comment 0298-13)
34.	Rather than setting a stringent health-based standard that the Yucca Mountain site
should meet to be licensed, the EPA appears to be creating a "two-tiered standard," which
is intended to help get the repository approved and open for business. DOE has publicly
estimated radiation doses of 250 millirem/year at 200,000 to 300,000 years in the future, so
EPA now proposes a standard above that level. Such blatant disregard for scientific
objectivity and public health is very disturbing. (Comment 0301-4)
35.	Furthermore, if accepted, EPA's proposed standards would be, by far, the worst
standards among those of developed nations. For example, the French high-level nuclear
waste repository program recommends limiting maximum doses, estimated to occur
hundreds of thousands of years into the future, to 25 millirem/year. The proposed EPA
limit beyond 10,000 years (350 millirem/year) would allow more than ten times higher
radiation doses than the limit recommended under the French repository program. The
Canadian repository program limits doses to about 10 millirem/year for 10,000 years but
does not allow a sudden increase after that period. The EPA proposal would allow a sudden
jump from 15 millirem/year to 350 millirem/year after 10,000 years, a 23-fold increase.
(Comment 0301-11)
36.	the agency has leapt from that well-defended position to a proposed standard of 350
millirem per year in year 10,001 was something EPA staff could not explain at all when
asked at the Amargosa Valley, NV, Hearing on October 3rd. (Comment 0306-1)
37.	Year 10,001 to 1,000,000: While EPA claims that "Phase II" of their standard, 350
millirem per year from years 10,001 to 1,000,000, is consistent with other nations, I do not
find compatible evidence. This limit is more than 10 times higher than France's goal for
long-term high-level waste, and 35 times higher than Canada's, next door. (Comment
0306-8)
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38.1 fail to understand why you have proposed a two part standard for the dumpsite when
the Court rejected the standard you had previously. It is my understanding that the Court
threw out the 10,000 year standard because it was in conflict with the recommendations
that you were supposed to follow - and here you go putting the same rejected standard back
again. The only standard should be the peak dose one. (Comment 0261-1)
39.	EPA's proposed a two-tiered system that would permit a 15 millirem per year dose
limit from Yucca Mountain for the first 10,000 years, but which would suddenly rise to an
unacceptable 350 millirem per year, after the first 10,000 years has elapsed. Such an
increase flagrantly ignores the law and the findings of the NAS, by establishing a two-
tiered system which allows a far greater level of exposure to radiation after an arbitrary
coverage period of 10,000 years. I have serious concerns about a two-tiered system that
allows higher radiation exposure levels at Yucca Mountain in the future, given that the
longer that the waste is buried there, the more deadly it will become over time. The
National Academy of Sciences spoke clearly when it said this standard should cover the
peak levels of danger created by waste slated to go to Yucca Mountain. It must be noted
that the NAS found in June of this year that radiation exposure at any level increases cancer
risks, and that there is no safe threshold. (Comment 0271-2)
40.	EPA's and NRC's proposed double standard be withdrawn that protects people for the
first 10,000 years to currently applied standards of protection, but dooms future generations
after that time to a 1 ¦} in 36 cancer rate (or even worse), and. a 1 tin 72 fatal cancer rate (
or even worse). Such proposed cancer rates and fatal cancer rates are horrifying, and both
agencies must withdraw such an unacceptable proposal. This is a complete violation of
principles of intergenerational equity, justice and morality. (Comment 0310-1)
41.	EPA's two-tiered approach is not based upon and consistent with the recommendations
of the NAS. It fails to comply with EPA's fundamental charter as specified in the NWPA
and 1992 EnPA - to protect public health and the environment. (Comment 0311.1-3)
42.	EPA's two-tiered approach is the same as the initial approach that was vacated. DOE
assumes that the engineered barriers will not corrode or leak for the first 10,000 years.
Also, DOE's models suggest that once the barriers fail and waste begins to migrate, a
median peak of 300 mrem/yr will result and will continue for thousands of years. NAS
recommended that "it is not reasonable to assume that a system for post-closure oversight
of the repository can 'be developed based on active institutional controls, that will prevent
an unreasonable risk of breaching the repository engineered barriers or increasing the
exposure of individual members of the public to radiation beyond allowable limits.
Additionally, there is no technical basis for making forecasts about the long-term reliability
of passive institutional controls such as markers, monuments, and records." EPA
responded with a standard that DOE can meet. (Comments 0311.1-5 and 0311.1-10)
43.	No country has proposed a standard as lax as that proposed by the EPA. No other
standard that has been proposed for times beyond 10,000 years would allow such lax long
term rules. (Comment 0314.1-4)
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44.	The second tier standard of 3 ,5mSv for the period from 10,000 years post -closure up
to one million years is inadequate to protect future generations of Clark County residents.
The long-term standard is roughly twenty times higher than the short-term standard and it
is unclear what the rationale is for such a large discrepancy. (Comment 0327-1)
45.	for an allowable post-closure dose of 350 millirem CEDE per year proposed by EPA
for years 10,000 to 1,000,000 in the distant future, unquestionably 350 mrem/yr is entirely
unacceptable. (Comment 0331-3)
46.	The new radiation standard for Yucca Mountain is contrary to internationally accepted
radiation standards. (Comment 0342-1)
47.	The proposed standards represent a large -scale weakening of environmental and public
health protection standards and are the worst such standards, by far, in the Western world,
in violation of international norms. (Comment 0349-3)
48.	We do not accept EPA's reasoning that a two tiered standard is necessary. The rule does
not adequately explain why the 15 millirem per year standard for less than 10,000 years
should not apply beyond 10,000 years. The rule also does not adequately address the
fundamental challenge: to have a standard that is protective of public health and safety at
the time of maximum releases into the environment. The rule should be written to protect
public health and safety rather than to accommodate the many flaws in the site, and the
site's inability to contain the radiation. (Comments 0353-3 and 0361-3)
49.	1. How did EPA go from 15 to 350, and aren't we talking about these numbers in
addition to natural background levels? (Comment 0367.1-5)
50.	Why isn't it safe to be exposed to 350 millirems today if it is safe in 10,000 years?
(Comment 0367.1-11)
51.	Unfortunately the rules that we are looking at, and as we've examined them, are weaker
than the original standards. They do propose and argue a dramatic reversal of international
and public health standards. And we do believe that there is a two-tiered system, a double
standard. (Comment 0368.2-2)
52.	I'd like to point you to the French standard, ... the French regulation says that for the
short term, you make accurate ... calculations and you meet your 25 millirem limit with
reasonable best estimate parameter characterization. And for the long term, you actually
have conservative or upper bound parameter characterizations because you cannot do
characterization, but you still have to meet the same dose limit. ... let me recommend a
specific alternative to you for a standard which would be somewhere between 10 and 25
millirem for the effective dose equivalent per year from all pathways with a sublimit for
four millirem per year from drinking water. (Comment 0368.3-7)
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53.	We find the two-tiered dose limits for before and after 10,000 years to be an
appropriate recognition of the greater degree of uncertainty for the longer period.
(Comment 0368.5-1)
54.	Extending the concept of individual dose standard to one million years is meaningless
when the standard after 10,000 years is 14 times greater than what EPA itself has stated is
protective of public health and more than 23 times higher than the first 10,000 years. In
fact, EPA's proposed rule is the least protective radiation standard in the world. No other
U.S. or international protection standard emits a dose of 350 millirems per year to
individuals. (Comments 0368.6-2 and 0368.13-4)
55.	We believe the EPA's recently revised standard , ... fails to comply with the court
ruling and the intent of the National Academy of Sciences' recommendations. Instead of
extending the 15 millirem per year limit through the time of peak risk, EPA has proposed
the two-part standard 15 millirem per year for 10,000 years and then the 350 millirem per
year standard thereafter which would be at two million years. Such a standard is not
scientifically justified and would perhaps be the least protective radiation standard in the
world. No other U.S. or international radiation protection standard permits a dose of 350
millirems per year to individuals. And, in fact, EPA's proposed standard is not even
consistent with the agency's own previous recommendations. (Comment 0368.7-1)
56.	I'm here to express our shared concern and opposition to the dangerous double
standards recently set for radiation regulations at Yucca Mountain. (Comment 0368.12-1)
57.	Nevada has heard some Yucca Mountain proponents recently draw favorable
comparisons between EPA's proposed rule for Yucca and the Finnish standard,
promulgated by its Radiation and Nuclear Safety Authority ("STUK"). In fact, as
explained below, the Finnish standard.. .is far more protective and responsible than what
EPA has proposed for Yucca. Indeed, the two standards are night and day.
First, the STUK standard requires that the maximum radiation dose over long time
scales be comparable to that from naturally occurring radioactive substances.
Communications between the State and STUK have confirmed that this refers to doses
from radionuclides of terrestrial origin, to the exclusion of doses from atmospheric fallout,
cosmic radiation, natural radionuclides in houses such as radon, and other human-enhanced
impacts. This means that the STUK standard is on the order of 50 mrem per year for the
maximum, in contrast to EPA's proposed post-10,000-year standard of 350 mrem per year
for he median dose, or about 1000 mrem per year for the mean dose, to EPA's Reasonably
Maximally Exposed Individual (RMEI).
Surely it cannot be EPA's position that the citizens of Nevada deserve less
protection than the Finns. (Comments 0399-1 and 0401-1)
Response to Issue A:
Many of the comments arguing against having different dose limits over different time
periods offered similar reasoning to the comments addressed in Section 2, Issue C ("extend
the use of 15 mrem CEDE/yr to the time of peak dose"). These points include the
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justification for a different, higher dose limit beyond 10,000 years, the legality of the
proposal or its consistency with the NAS recommendation, the risks presented by the
proposed post-10,000-year dose limit, intergenerational equity, and comparability with
international standards. See the earlier section for additional discussion.
The comments were generally phrased in relation to the proposed peak dose standard of 3.5
mSv/yr (350 mrem/yr). In our final amendments, however, we are not establishing the
proposed 350 mrem/yr level as our final peak dose standard; instead, we are establishing 1
mSv/yr (100 mrem/yr) as the public health and safety standard to apply for the period
beyond 10,000 years and up to 1 million years. As discussed in the preamble to the final
amendments, a dose level of 100 mrem/yr level is well-established as protective of public
health and as such represents a standard that is protective of public health and safety in the
extreme far future. (70 FR 49040) International organizations such as ICRP, IAEA, and
NEA recommend its use as an overall public dose limit in planning for situations where
exposures may be reasonably expected to occur. Domestically, both NRC and DOE
incorporate the 100 mrem/yr level into their systems of regulation (10 CFR 20.1301 and
DOE Order 5400.5, respectively), and NCRP also endorses the ICRP system of protection
(NCRP Report 116, "Limitation of Exposure to Ionizing Radiation," Docket No. EPA-HQ-
OAR-2005-0083-0407). Because we are adopting the same approach described in our
proposal, however, we are responding to the comments on this topic.
Commenters 0353 and 0361 charged that we have established a standard to ensure the site
can be licensed. Commenter 0311.1 claims that the proposed approach is "the same as the
initial approach that was vacated." The commenter then cites a finding of the NAS
committee that institutional controls cannot be relied upon to prevent human intrusion or
degradation of the repository. The commenter's point is not clear to us. This statement in
the NAS Report was made in response to a specific Congressional question using the same
language. There is no indication that DOE intends to rely on institutional control to
maintain the repository indefinitely, or that it will attempt to take credit for such controls in
its license application. Further, it is EPA's goal that a geologic disposal facility be able to
provide adequate containment and protection in the absence of maintenance or even if
knowledge of the facility is lost.
On the larger question of consistency with the NAS recommendation and Court ruling,
Commenter 0261 also believes we are "putting the same rejected standard back again."
Commenter 0368.7 agrees that our proposal "fails to comply with the court ruling and the
intent of the National Academy of Sciences' recommendations". Other commenters stated
that "Rather than suggesting any relaxation of the standard after 10,000 years," NAS only
qualified its recommendation by reference to geologic stability (Commenter 0226), and
"[ijmplicit in [the NAS] recommendation was the expectation that one size does fit all
when it comes to human beings and radiation exposure" (Commenter 0267, emphasis in
original). As discussed in more detail in Section 2 Issue C of this document, we disagree
with this interpretation of the NAS recommendation and Court ruling. NAS was silent
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regarding the level of the peak compliance standard, and explicitly declined to recommend
a level for that standard. Rather, NAS expressed its intent to leave that decision to EPA as
"not ultimately a question of science but of public policy." (NAS Report p. 5) In
discussing the range of risks represented by current domestic and international regulations
for EPA to consider, NAS noted that, while "there is a considerable body of analysis and
informed judgment from which to draw in formulating a standard for the proposed Yucca
Mountain repository," "EPA's process for setting the Yucca Mountain standard is
presumably not bound by this experience." (NAS Report p. 39) Finally, NAS
acknowledged that EPA was not constrained by its discussion of representative risks in
selecting the peak compliance standard, concluding that "other starting points are possible,
and of course the final rule could differ markedly from any of them." (NAS Report p. 3)
Because its concern was the determination of compliance at the time of peak dose, NAS
did not explicitly consider whether compliance might be judged against different standards
during the 1 million-year time frame, but implicitly acknowledged this possibility in its
discussion of intergenerational equity (see also Section 9 of this document). We believe
there is ample evidence that NAS recognized that the nature of the assessments changes
and effectively becomes more stylized as the period covered by the assessment increases
(see, for example, its many references to "bounding" approaches), although the committee
did not address different assessment time frames. We believe it is reasonable to conclude
that the nature of the compliance determination may also change as the assessment period
grows longer. We find 10,000 years to be a reasonable transition time, as there is a
considerable body of experience in conducting assessments for such periods. Further, as
noted in Section 2, in his personal testimony before a Senate committee on March 1, 2006,
Robert Fri, chair of the NAS committee, indicated that, in his opinion, a compliance
standard changing over time would not necessarily be inconsistent with the NAS
recommendation to assess compliance at the time of peak risk. He suggested that such an
approach could be viewed as reducing "the risk of excessive conservatism." (Docket No.
EPA-HQ-OAR-2005-0083-0380)
Commenters 0111, 0211.1, 0219, and 0367.1 question the "significant one-year increase in
allowable exposure." They question why 350 mrem/yr would not be considered protective
today, if it is protective for periods beyond 10,000 years. Commenter 0111 cites our
"unprecedented" attempt to "set expiration dates for public health standards." Commenter
0223 similarly states that standards should be "degraded" only for "legitimate" and
"performance based" reasons, and "not simply because a time limit has passed." The
commenter urges us to establish a protective standard "which can always be reviewed over
time." Our justification for the higher dose standard beyond 10,000 years is in part
performance-based. We have discussed at length our concerns that modeling as a tool for
decision-making has limitations over long time frames, and that these limitations are
accentuated when significant uncertainty is present in the system being analyzed. In our
view, the results of such analyses should not be considered to be accurate predictions, but
rather estimates of performance given certain assumptions regarding the characteristics of
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the disposal system. (See NAS Report p. 71) We acknowledge that we cannot say exactly
when these uncertainties become unmanageable or overwhelming. We assume the
commenter is suggesting that, in the future, were we to identify a specific point at which
the quality of projections renders them less credible, it would be "legitimate" to modify the
rule to insert time-dependent standards for the longer-term. While we can re-visit
regulations if necessary, we are not sure when this would be expected to happen. Our
standards have a broader place in the regulatory structure, as demonstrated by the next
comment.
Comment 0367.1-5 questions the difference in the two dose limits and how the higher
proposed limit after 10,000 years is justified. In both the proposal and in selecting the final
peak dose standard of 100 mrem/yr, we attempted to balance a number of factors, including
the ability to reasonably model the disposal system far into the future, dose levels that
would adequately protect the public, and the role of the compliance standard in the
licensing process, to identify a level that would be appropriate for the entire period out to 1
million years. During the period immediately beyond 10,000 years, we anticipate that
projected doses would not exceed the peak dose standard; however, an acceptable result
will not by itself demonstrate that the disposal system is safe and will perform adequately.
Should projected doses show a significant rate of increase during that period, NRC will
make judgments as to whether that would indicate unacceptable degradation of the
engineered barriers that will result in a less-than-reasonable expectation that the overall
performance is acceptable.
As for the second part of the commenter's question, both the 15 mrem/yr and the peak dose
standards refer only to doses caused by releases of radionuclides from the Yucca Mountain
disposal system, as directed by the EnPA. Background radiation doses, or doses from other
sources (such as medical applications), are not included in those standards. We have not
derived the final peak dose standard from an analysis of specific estimates of background
radiation. We note, however, that the 100 mrem/yr peak dose standard reasonably
comports with an analysis from that perspective as well. For example, it is comparable to
outdoor (unshielded) measurements of cosmic and terrestrial radiation in Amargosa Valley.
When shielding from buildings is considered and indoor radon doses are estimated using a
more conservative conversion factor suggested by some commenters, 100 mrem/yr is at the
low end of overall background radiation estimates in Amargosa Valley and nationally, and
is within the difference between average estimates among counties in the State of Nevada.
(Docket No. EPA-HQ-OAR-2005-0083-0387) This suggests that releases from the Yucca
Mountain disposal system potentially leading to doses of 100 mrem/yr to the RMEI will
result in total doses lower than those incurred by residents of other parts of the country
from natural sources alone. Further, the projected doses would be incurred by only the
RMEI, who is defined to be within the most highly-exposed segment of the population near
Yucca Mountain. Most of the population would incur much lower doses, if any.
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Commenter 0211.1 further asks "how DOE will demonstrate through performance
assessment" that it complies, given the increased dose limit beyond 10,000 years. This
commenter actually touches on another of the factors that led us to propose a higher dose
limit for the long-term, which is its place in the licensing process. Consistent with the NAS
recommendation to assess compliance at the time of peak risk, within the period of
geologic stability, the compliance period for our standards will extend up to 1 million
years. We believe it is likely that peak dose will occur sometime after 10,000 years,
although we cannot say exactly when (we note that some commenters raise the possibility
that the peak dose will actually occur earlier than 10,000 years). DOE's previously
published performance assessments suggest that peak doses will occur sometime in the
period between 200,000 and 500,000 years. We strove to establish a standard that would
protect public health and safety and appropriately balance the factors important to
regulatory decision-making over very long times, the relative confidence that can be placed
in projections over different time frames, and the nature of the current generation's
commitment to future generations, as well as how that commitment can be demonstrated.
We judged that the best approach would be to identify a level that balanced these factors
for the entire period up to 1 million years, while maintaining the 10,000-year standard as a
point of departure that focuses on the early evolution of the repository, when thermal
stresses are most significant. Therefore, we have selected a standard that we believe is
appropriate at any time up to 1 million years. The 10,000-year standard then gives NRC a
basis forjudging the overall appropriateness of DOE's projections of disposal system
evolution over the longer-term, not just the results in comparison with the applicable
standard. This may be most important during the period relatively shortly after 10,000
years. Should significant releases be projected during that period, NRC will have to judge
whether such behavior indicates acceptable performance, even if the long-term peak dose
standard is met. We note that NRC staff stated to NRC's Advisory Committee on Nuclear
Waste (ACNW) that NRC would "look at the basis for - as we would have [in the 2001
rule], that if the dose went beyond 15 in just after 10,000 years, what in the performance
assessment is causing that to occur, and why?" (Docket EPA-HQ-OAR-2005-0083-0376,
p. 49). It may in fact be impossible for projected doses to exceed, or even approach, 15
mrem/yr within 10,000 years without also exceeding the peak dose standard at some other
time during the compliance period. The 10,000-year standard would not, then, control
projected doses during that period but would instead represent an explicit statement of the
level of performance that is required to be achieved by the peak dose standard in that initial
period. See Section 6 of this document for discussion of uncertainty in performance
projections.
Several commenters (0175, 0177, and 0310) contend that our proposal would "doom"
future generations and lead to "horrifying" cancer rates. They estimate a cancer incidence
figure of 1 in 36 as resulting from a 350 mrem CEDE annual dose. Consistent with the
direction of the EnPA and the recommendations of the NAS, our peak dose standard of 100
mrem/yr will protect public health and safety. The nominal annual risk associated with this
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standard, applying current risk estimates, is 5.75 x 10"5, which is comparable to the range of
risks represented by domestic and international standards NAS suggested that EPA
consider, "all of which are consistent with recommendations from authoritative radiation
protection bodies." (NAS Report p. 49 and Tables 2-3 and 2-4). When the extended time
frames addressed by the peak dose standard are taken into account, with the attendant
uncertainties, this is a reasonable level of risk. We conclude that our standards will protect
public health and safety, as required by the EnPA. See Section 2, Issue H, and Section 5 of
this document for discussion of radiation impacts.
Commenter 0271 questions the proposed higher dose limit because "the longer that the
waste is buried there, the more deadly it will become over time." We assume the
commenter means that over time it is more likely that releases from the repository will
reach the accessible environment, and that for some period of time doses resulting from
those releases will increase. After that period, however, doses will decrease. The
commenter's statement could also be interpreted to suggest that early releases would be
less "deadly" and therefore should be encouraged (the waste itself will over time become
much less toxic). We do not believe it was intended in this way. Recognizing that some
releases are inevitable, such an approach would be directly counter to the fundamental goal
of geologic disposal to delay the period of release for as long as possible.
Other commenters also made statements requiring some interpretation. Commenter 0209.6
refers to regulations for nuclear power reactors in also concluding that our standard "fails
to protect the public in the first 10,000 years." The commenter specifically cites 10 CFR
part 50, Appendix I, Section 2A, which limits exposures to individuals in "unrestricted
areas" (including members of the public) to 3 mrem/yr to the total body or 20 mrem/yr to
any organ from calculated liquid effluents. It appears the commenter is using this
restriction as an indication that our 15 mrem CEDE/yr standard for the initial 10,000-year
period is not protective when compared to these effluent limits, and further objects that we
have accepted the "false premise" that no waste package failures will occur within the first
10,000 years. However, the commenter fails to refer to Sections 2B and 2C of the same
appendix, which contain separate limits on gaseous and particulate effluents, respectively.
Taken together, and depending on the mix of radionuclides involved, the effluent standards
cited do not differ significantly from the 15 mrem CEDE level. In addition, we do not
believe that a standard for nuclear power operations can be reasonably compared to a
standard for waste disposal applicable to the extreme far future.
Similarly, Commenter 0210.1 believes "the two-tier radiation standard is not stable" and
asks how we can "be certain that the standards will protect people one million years in the
future?" The commenter asks this question in recommending that further research be done
on reprocessing of spent fuel and alternatives to geologic disposal. We are unsure what the
commenter means by "not stable". We discussed earlier the application of NRC judgment
at different times in concluding that the disposal system will perform adequately.
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Similarly, we are not sure whether the question regarding protectiveness at "one million
years in the future" is suggesting that humans may have developed more sensitivity to
radiation over time, or that we can't be "certain" because we cannot independently verify
that actual exposures at such times will be adequately represented by dose projections
performed today. On the first point, we have taken the approach, as recommended by NAS
and employed previously at WIPP and in various international standards (e.g., the French
and Swedish standards referenced below), that it is not reasonable to project changes in
human technology, society, or biology over long periods, as there is no basis for selecting
one possible future over another. Therefore, we assume that the RMEI is representative of
today's population in its response to radiation. On the second point, geologic disposal was
never envisioned as a technology that would rely upon monitoring to confirm modeling
projections. In fact, as we have stated before, it was understood to be a technology that
must operate passively to protect public health independently of monitoring, maintenance,
or even human knowledge.
In raising a number of points already addressed, Commenter 0267 charges that, in
emphasizing uncertainties, we have avoided addressing certainties, and are instead relying
on "wishful thinking" and "hope" that the worst will not occur. The commenter presents
this view in terms of early failure of the engineered barriers, limitation of the human
intrusion scenario, future geologic and climatic events and processes, harm resulting from
actual exposures, and "that the future over which we have no control will present no
surprises we haven't already imagined and taken into account."
However, we believe we have addressed these factors appropriately, and would argue
against a "worst case" approach as inconsistent with the principle of "reasonable
expectation." As we have mentioned before, assumptions regarding failure of the
engineered barriers and the potential for early releases will be subject to NRC judgment,
which will not focus exclusively on projected outcomes (doses), but which we expect to
consider the overall approach to assessments (see EPA-HQ-OAR-2005-0083-0376, p. 45
for considerations in NRC's evaluation of "reasonable expectation"). The intrusion
scenario is consistent with the NAS recommendation to test the "resilience" of the
repository (if the intrusion is a deliberate attempt to disrupt the repository, there is no basis
to judge the potential results); it assumes the intrusion will occur. The presumed scenario,
exploration for water, must be considered to be conservative because water in the region is
much more accessible at lower elevations and lower recovery costs. The assumption
regarding use of current drilling technology is consistent with the overall NAS approach to
human biology, society, and technology (we note that the French standard referenced
below adopts the same approach to drilling technology). Regarding seismicity and climate
change, DOE will consider highly disruptive seismic events using probability relationships
derived from historic events. We did not specify how future climate should be represented,
although we did state that it could be represented by constant (future) conditions for the
period up to 1 million years. We believe this approach would capture the important aspects
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of climate change (flow of water through the repository) and is consistent with the NAS
position. We also believe that arbitrarily imposing climate fluctuations, particularly the
timing and magnitude of precipitation changes, adds an unnecessary speculative aspect to
the dose projections (see the Yucca Mountain FEIS to see how such fluctuations affect
dose projections). The timing and magnitude of such cycles is essentially unknowable, and
we note that some researchers believe that future glacial cycles will be delayed and the
current climate at Yucca Mountain is a better representation of future climate than cooler,
wetter conditions. (See Section 8 of this document for discussion of climate-related
comments.) As for potential exposures, the limit we have established for these long times
is consistent with the overall public dose limit widely adopted as protective today (as stated
earlier, however, it will not be possible to verify these projections with monitoring data).
Finally, we have considered whether there might be fundamentally different processes or
events in the far future than are known or expected today. We were unable to identify any
such "surprises" (although perhaps by definition they would be unidentifiable), and do not
believe there is a basis for speculating about the potential effects of unknowable influences
on the disposal system.
Commenters 0180 and 0181 appear to accept that a higher peak dose standard is
appropriate and offer an interesting suggestion to correlate the timing of the change in the
dose standard to the failure of the engineered barriers, rather than specifying a point in
time. The commenters correctly point out that "container integrity lifetime will be the
primary determinant as to the protection afforded by the engineered barriers" and propose
that the standard change "in that year or period after which the engineered barriers are
expected to fail completely and when protection will be provided only by the natural
barriers." In this approach, a "dose-based compliance standard should be applied up to the
time when the peak package dose is expected to occur - risks after that point will decrease
as a result of natural attenuation in the waste package." We are uncertain how to interpret
this proposal. If a change in the dose standard would come after the engineered barriers
"fail completely," this could be interpreted to mean that as long as a single waste package
retains some of its contents, the initial dose standard would apply. As waste packages will
probably fail over an extended period of time, this could be the case for close to 1 million
years, when the natural barriers are already likely to have provided the only protection for
the bulk of the radionuclide inventory for a very long time. It could also intend that an
average time of failure should be estimated and used as the transition point for the dose
standard. However, we are also uncertain how to interpret the reference to the "peak
package dose." This could refer to the peak radionuclide inventory in the package, or
possibly to the peak dose attributable to a single waste package. These are two very
different things. While this comment presents an interesting approach, because of the
uncertainties in determining when the "peak package dose" would occur, we do not see a
clear way to formulate a safety standard using such an approach.
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Several commenters again mentioned the compatibility of our proposal with international
standards and guidance. Because we referred in our proposal to a number of international
sources, both from bodies such as the IAEA and NEA and from specific countries, such as
Sweden, as sources of general guidance or as examples of specific regulatory approaches,
we are very interested in commenters' views on this topic. In general, we find few
similarities in the details of the international approaches that are directly applicable, and no
clear basis for comparing the different approaches. At the same time, we did find broad
points of similarity in the overall approach to long-term projections.8 Much of the
guidance we cited is open to interpretation (some of it deliberately so, in order not to
foreclose different approaches that may be crafted to comply with specific national legal or
regulatory contexts). While we do not claim that our interpretation must be the only viable
one, we believe our approach is reasonable and consistent with international guidance and
approaches in their views of projecting and interpreting dose and risk for the extreme far
future. Where we must depart from the common path is in our statutorily-directed mandate
to establish a quantitative compliance standard. The more typical approach internationally
is to require compliance with quantitative performance assessment for only a limited period
of time (in some cases, less than 10,000 years). Longer-term dose projections may be
compared to dose or risk targets or reference levels, but are viewed more as qualitative
indicators of performance than as "accurate predictions of the expected behavior of a
geologic repository" (NAS Report p. 71), to be weighed in conjunction with other
qualitative arguments for confidence in the overall safety of the facility. At longer times,
the weight given to quantitative projections typically decreases.9 We must determine how
8	"National programmes which have already established such criteria have generally found it possible to make
cautious, but reasonable assumptions to extend the use of radiological limits already applied to contemporary
activities for several thousands of years. The greater challenge lies in setting criteria for very long time
frames, extending to a million year and beyond, for which safety analyses must account for high uncertainty
and for which the understanding of the needs and impacts on future generations become increasingly
speculative." ("Regulating the Long-Term Safety of Geological Disposal: Towards a Common Understanding
of the Main Objectives and Bases of Safety Criteria," NEA-6182, 2007, pp. 20-21).
9	The 2007 NEA document on "Consideration of Timescales in Post-Closure Safety of Geological Disposal of
Radioactive Waste," which is based on surveys of NEA Member Countries, states "Calculated values of dose
and risk are therefore viewed in regulations not as predictions but rather as indicators or measures of
protection that are used to test the capability of the system to provide isolation of the waste and containment
of radionuclides (the 'dose' that is being calculated is what radio-protectionists refer to as 'potential dose').
These indicators are to be evaluated on the basis of models that include certain stylized assumptions, in
particular regarding the biosphere and human lifestyle or actions." (p. 38)
Similarly, ICRP Publication 81 contrasts the approach of "consideration of quantitative estimates of dose or
risk on the order of 1000 to 10,000 years" with "consideration of quantitative calculations further into the
future making increasing use of stylized approaches and considering the time periods when judging the
calculated results. Qualitative arguments could provide additional information to this judgmental process."
(Paragraph 71)
In its most recent recommendations, ICRP notes that "In Publications 77 and 81, the Commission recognized
that both the individual doses and the size of the exposed population become increasingly uncertain as time
increases. The Commission is of the opinion that in the decision-making process, owing to the increasing
uncertainties, giving less weight to very low doses and to doses received in the distant future could be
considered." (Publication 103, Paragraph 222)
The IAEA consensus document for geologic disposal ("Safety Requirements for Geological Disposal of
Radioactive Waste," WS-R-4, 2006) states: "It is recognized that radiation doses to individuals in the future
can only be estimated and that the uncertainties associated with these estimates will increase for times farther
into the future. Care needs to be exercised in using the criteria beyond the time when the uncertainties
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best to satisfy our statutory mandate, consistent with the NAS recommendations, while
recognizing the uncertainties and complexities that lead to the view that longer-term
projections are qualitatively different from relatively near-term projections.
With few exceptions, we received only statements that our proposal "would be the weakest
standard in the world" or is otherwise inconsistent with international practices, without
specific reference to points of disagreement or contrary examples. We disagree and will
discuss international approaches in some detail.
Comment 0226-122 generally criticizes our "demonstrably false" statements that we "need
not be consistent with international precedents, because those precedents do not address
long time frames." However, we made no such statements. We have pointed out in our
proposal, our final rule, and in some detail below, that the typical approach internationally
is not to require compliance with a strict quantitative limit at very long times. This is the
approach we adopted in our 2001 rulemaking, in which the regulatory authority considers
projected doses in a more qualitative sense in the overall determination of disposal system
safety. The appendix referred to in the comment (Docket No. EPA-HQ-OAR-2005-0083-
0227) cites references in our proposal to NEA and UK sources as "selective and
misleading," because the cited documents provide no justification for a different approach
to assessments at 10,000 years. (70 FR 49035 and 49037, respectively) The commenter
acknowledges that these sources recognize that at some point the underlying basis for the
assessment may change, but points out that "radiological risk remains a key indicator" even
over very long time frames. We believe the commenter is confusing two concepts, the
conduct of dose assessments and the establishment of dose standards. We do not question
that longer-term projections can provide useful information; as noted above, we required
such projections in our 2001 rule. However, there is a significant difference between
viewing such projections as "key indicators" and determining compliance against a
quantitative dose limit. The commenter notes, as we stated in our proposal (70 FR 49033),
that "the compliance criterion in the UK is a target not a limit, i.e., compliance with it is not
absolutely required." The commenter then points out that the target applies for the entire
assessment period, and seems to assume that long-term doses will be judged acceptable
only if they exceed the target by only a limited amount. This assumption, however,
represents exactly the problem we see with the "dose target" approach. Such conclusions
regarding acceptable doses cannot be reached in advance of the actual assessment. Unless
such considerations are established in regulation, there is no basis to assume that the
projected dose can exceed the target by only a certain amount, or under specific
circumstances or for specific reasons. Thus, we see no basis in the comment's assertion
that "none [of these international approaches] permits the type of increase in risk" that the
commenter sees with our proposed peak dose standard (the comments were, we note again,
related to the proposed 350 mrem/yr peak dose standard). It cannot clearly be stated
whether a dose target "permits" such judgments or not. (See also Section 9 of this
document for additional discussion of this point as it relates to intergenerational equity.)
Commenter 0368.3 offers a specific recommendation to consider the French standard for
geologic disposal. The commenter describes this standard as requiring "reasonable best
become so large that the criteria may no longer serve as a reasonable basis for decisionmaking." (Paragraph
2.12)
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estimate characterization" in the short term, with "conservative or upper bound parameter
characterizations, because you cannot do characterization, but you still have to meet the
same [25 mrem/yr] dose limit." The commenter concludes that an appropriate standard for
the long-term at Yucca Mountain would be an individual-protection limit between 10 and
25 mrem/yr with continued ground-water protection.
We disagree with the commenter's characterization of the French standard (Basic Safety
Rule No III.2.f, "Disposal of Radioactive Waste in Deep Geological Formations," 1991,
Docket No. EPA-HQ-OAR-2005-0083-0389). First of all, the standard is very clear that
the 25 mrem/yr dose level is not viewed as "the same dose limit" throughout the entire
period of disposal system evaluation. For the initial period, which is to last "at least 10,000
years.. .The limit of [25 mrem/yr] will be applied for determining the acceptability of the
radiological consequences." However, "[bjeyond this period" when "uncertainty
concerning the evolution of the repository increases progressively with time.. .Quantified
estimates of the individual dose estimates must then be made. These may be
supplemented, by more qualitative assessments of the results of these estimates, as regards
the geological barrier evolution factors, so as to verify that the release of the radionuclides
does not result in an unacceptable individual dose. In this verification, the same [25
mrem/yr] limit shall be used as a reference value " (Section 3.2.1, emphasis added) Thus,
although the value is the same, 25 mrem/yr no longer "determin[es] the acceptability of the
radiological consequences" (i.e., a strict compliance standard). This difference in wording
is instructive, as it strongly indicates that doses that would be unacceptably high in the
near-term would be acceptable at later times, as long as other arguments for the overall
safety of the disposal system are considered valid. Regarding Yucca Mountain, we could
conceivably have written our 2001 standard using similar language, e.g., that DOE should
accompany its peak dose projections with a description of qualitative factors affecting
those projections, and show a comparison to 15 mrem/yr "as a reference value." However,
we doubt whether the commenter would have viewed such a statement as requiring DOE
"to meet the same limit." Essentially, our 2001 standard as promulgated took the same
broad approach as the French standard (and other international standards discussed below)
by leaving NRC discretion as to how much importance to give quantitative dose
projections, taking into account other qualitative information regarding the overall safety of
the disposal system, over periods of hundreds of thousands of years.
It is useful to examine other aspects of the French standard for comparison to the approach
we have adopted at Yucca Mountain, and more generally in 40 CFR part 191. The 25
mrem/yr standard in the French regulation applies only to "events which are certain or
highly probable" (characterized by the commenter as "reasonable best estimate"). In other
words, only the most likely evolution of the disposal system is judged against a quantitative
dose limit, and that strict judgment applies only for the initial period after disposal. These
"certain or highly probable" events do include some evaluation of climate and vertical
movement (uplifting and subsidence). However, "hypothetical" situations involving
"occurrence of random events" of natural or anthropogenic origin are evaluated separately.
In addition to more significant climatic or seismic effects, these "hypothetical" situations
include human intrusion and potential manufacturing defects in waste packages or other
engineered barriers that might lead to early failure (Section 5.3.2).
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In analyzing these "hypothetical" situations, "[wjhile consideration may be given to using
the risk concept.. .to allow for the probability of occurrence of each situation giving rise to
exposure.. .it can be expected to be difficult, if not impossible, to estimate the probabilities
of the events which can result in exposure...Therefore, individual exposure expressed as a
dose equivalent, associated with hypothetical situations for which allowance must be made
in the design of the repository must be maintained well below levels liable to give rise to
deterministic effects." (Section 3.2.2, emphasis added) Deterministic radiation effects are
dependent not only on the radiation dose, but the time over which that dose is delivered.
Levels resulting in deterministic effects are usually considered to be about 50 rem or
higher, if the dose is delivered over a few hours, or at most, days (there are indications that
some deterministic effects could result from acute doses of about 20 rem). However, it
would be highly unusual to project such acute doses from a geologic disposal facility,
where radionuclides must travel for extended periods through the natural geology before
reaching a receptor. Conceivably, such acute doses could be incurred by an intrusion in
which a person comes into direct contact with the waste layer itself, particularly early after
disposal, when a significant inventory of short-lived fission products may still be present.
However, the safety of geologic disposal has never been predicated on its ability to prevent
an intrusion of this nature or to protect the intruder in such a situation. (NAS Report pp.
114-115) A cataclysmic volcanic eruption in which a significant quantity of waste is
directly ejected onto the surface might be another situation leading to acute doses. In such
an event, however, it is likely that the destructive nature of the eruption itself would be the
overriding concern of the affected population. We note that the Finnish standard, discussed
in more detail below, also includes such a reference to deterministic effects, characterizing
such a level as "dose above 0.5 Sv [50 rem]". Again, for purposes of assessing the safety
of the disposal system, such a dose would likely be calculated as an annual dose. A dose of
50 rem delivered over a year would not be expected to result in deterministic effects.
We note that the commenter's statement regarding "conservative or upper bound" analyses
does apply to natural events such as extreme climate change or seismicity, where "the
maximum earthquake physically possible shall be investigated on the basis of the tectonic
context of the site". Climate change also requires that "[gjlaciation.. .after 160,000 years
with a conservative evaluation of the extension of ice shall be allowed for." (Appendix 2,
Section 2) It is not clear what "conservative" means in this context, as a more limited
extension of ice would probably permit different types of receptors to be considered. If ice
is extensive, it may not be possible for human receptors to be present in an area affected by
radionuclide release. This type of climate change effect is fundamentally different from
that expected at Yucca Mountain and DOE will need to support its assumptions regarding
early failures.
This overall approach has some significant differences from those applied at Yucca
Mountain and WIPP. This is not to say that one approach is right and the other wrong, but
the differences must be understood in order to appreciate how safety is demonstrated in
each case. With the exception of the human-intrusion standard for Yucca Mountain, which
was developed as a "stylized" scenario consistent with the NAS Report and conditions at
Yucca Mountain, "hypothetical" situations are integrated through probabilistic sampling
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into the individual-protection analyses. At WIPP, intrusion scenarios based on historic
rates of mining and drilling are drivers for the individual-protection standard, while under
the French approach such scenarios might be assessed only as to whether the consequences
might be extremely high. Similarly with seismic activity, where the "maximum earthquake
physically possible" is assigned a probability of occurrence based on the observed historic
record, rather than evaluated in a separate order-of-magnitude analysis. And although we
have received a number of comments questioning DOE's estimates of waste package
lifetime, consideration of the potential for early failure of packages or other engineered
barriers caused by manufacturing defects have been incorporated into its individual-
protection analyses for Yucca Mountain.
We believe this comparison is useful because it illustrates one of the fundamental concerns
we expressed in our proposal, namely the emphasis that should be given to low-probability,
high-consequence events as compared to more "expected" situations. It is not clear that
evaluating a "worst case" seismic event in a separate analysis necessarily leads to a specific
conclusion regarding the overall safety of the disposal system or the advisability of design
changes to mitigate the potential effects of an event that has a very low probability of
occurrence. Nor is it clear that such an analysis adequately captures the range of potential
effects of lower-level (but not necessarily "limited and predictable") seismic events
throughout the life of the disposal system, as will take place at a seismically active site such
as Yucca Mountain, or that the effects from a combination of different events would be
evaluated. We recognize, however, that similar questions regarding the probabilistic
modeling approach also exist, in the sense that the full impact of a high-consequence event
may not be appreciated if it is tempered by a low probability of occurring.
It is also instructive to consider the approaches taken by other countries. We discussed the
Swedish approach in our proposal, but feel that certain aspects are worth emphasizing.
Like the French standard, the standard issued by the Swedish Radiation Protection
Authority (SSI, formerly the Swedish Radiation Protection Institute) (SSI FS 1998:1,
"Regulations on the Protection of Human Health and the Environment in Connection with
the Final Management of Spent Nuclear Fuel and Nuclear Waste," Docket EPA-HQ-OAR-
2005-0083-0047) includes a numerical standard during the initial period after disposal and
adopts a more qualitative approach at later times. Specifically, for the first 1,000 years
following closure of a repository, "the assessment of the repository's protective capability
shall be based on quantitative analyses of the impact on human health and the
environment." (Section 11) Thus, initially the performance projections may be used to
make decisions regarding the protectiveness of the disposal system. However, beyond the
first thousand years, "the assessment of the repository's protective capability shall be based
on various possible sequences for the development of the repository's properties, its
environment and the biosphere." (Section 12) This indicates that, even for periods within
10,000 years, quantitative projections no longer form the basis for judgments regarding the
overall safety of the disposal system, although they are still informative and will continue
to be important in decision-making, as described below. An estimate of collective
(population) dose over the first 10,000 years is also required (based on releases within the
first 1,000 years), although no standard is given in the regulation.
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In our proposal, we referred several times to draft guidance developed by SSI to
supplement its standards (Docket EPA-HQ-OAR-2005-0083-0048). That guidance (now
called "guidelines") is now final (SSI FS 2005:5, September 2005, Docket EPA-HQ-OAR-
2005-0083-0388). In its discussion of the role of quantitative risk analysis in
demonstrating disposal system safety, SSI notes that the final guidelines differ in some
important respects from the proposed guidance, providing more specificity regarding
inclusion of certain factors at different times in the disposal system's evolution. Thus, the
final guidelines state that "The period of time of a thousand years should be regarded as the
approximate time period for which a risk analysis can be carried out with high credibility
with regard to factors such as climate and biosphere conditions." However, for longer
periods up to 100,000 years, "Reporting should be based on quantitative risk
analysis... Supplementary indicators of the repository's protective capability, such as
barrier functions, radionuclide fluxes and concentrations in the environment, should be
used to strengthen the confidence in the calculated risks." The important consideration for
the timing of the analysis is whether the potential effects of large climate changes, such as
glaciation, are captured.
Similarly, for periods beyond 100,000 years, the final guidelines state that "A strict
quantitative comparison of calculated risk in relation to the criterion for individual risk in
the regulations is not meaningful. The assessment of the protective capability of the
repository should instead be based on reasoning on the calculated risk together with several
supplementary indicators of the protective capability of the repository such as barrier
functions, radionuclide fluxes and concentrations in the environment." Further, "[i]f the
calculated risk exceeds the criterion" or other "substantial disruptions" are indicated, "the
underlying causes of this should be reported on as well as possible measures to improve the
protective capability of the repository." The draft guidance states only that, for hundreds of
thousands of years, "the risk analysis may be based on a stylised description" of future
events and "The intention should be to shed light on the protective capability of the
repository and to provide a qualitative picture of the risks." Thus, while the overall
approach is still to place less reliance on quantitative performance projections in assessing
safety at longer times, and to supplement them with other arguments, both qualitative and
quantitative, the final guidelines are more forceful in placing those quantitative projections
at the center of the evaluation process.
The Finnish Radiation and Nuclear Safety Authority (STUK) has also issued regulations
for "Long-term Safety of Disposal of Spent Nuclear Fuel" (YVL 8.4, May 2001, Docket
EPA-HQ-OAR-2005-0083-0392). These regulations include two primary protection
standards. The first is an individual-protection standard of 10 mrem/yr (0.1 mSv/yr), which
applies to "an assessment period that is adequately predictable with respect to assessments
of human exposure but that shall be extended to at least several thousands of years."
(Section 2.2) Exposures are also to be assessed to a larger population, which may be
affected by surface water releases, and for which the dose constraint is lower by a degree
determined by the size of the exposed population.
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The second protection standard, which is implied to cover periods beyond the time for
which "human exposure" is "adequately predictable," is an activity release standard similar
to that included in 40 CFR part 191 and applied at WIPP, although these releases are
calculated on an annual, not cumulative, basis. This standard includes radionuclide-
specific limits on releases to the environment "from the expected evolution scenarios," but
that "may enter the environment not until after several thousands of years." These activity
releases have been calculated so that "at their maximum, the radiation impacts arising from
disposal can be comparable to those arising from natural radioactive substances," although
the standard itself does not define either "natural radioactive substances" or the "radiation
impacts arising" from them. We note this because we have received several comments
claiming that it is inappropriate to use sources of natural radiation as a basis for assessing
long-term impacts from disposal, and that our proposal was unique in discussing such
considerations. Like the French and Swedish approaches, the Finnish standard also
recognizes that "the importance to safety of such scenarios that cannot reasonably be
assessed by means of quantitative analyses" should be considered, and that the significance
of these "complementary considerations" "grows as the assessment period of interest
increases." (Section 4.4)
Comments 0399-1 and 0401-1 wish to rebut comparisons to the Finnish standard by
clarifying that the release limits in this secondary standard are based on maximum
projected releases, and would be expected to lead to doses no greater than about 50
mrem/yr (the commenter also addressed several points that are outside the scope of our
rulemaking, such as receptor and site characteristics). The commenter contrasts this with
our proposal to use the median of the distribution of projected doses for comparison with
the peak dose standard. We would point out, however, that it is not clear how the basis for
definition of the release limits themselves is related to the demonstration of compliance
with those limits. Stating that the limits are defined to represent the "maximum impact" is
not the same as requiring that they be compared to the highest projected releases. For
example, our cumulative release limits in 40 CFR part 191 were defined as a level that
would result in approximately 1,000 excess health effects over 10,000 years, per 100,000
metric tons of heavy metal. Compliance with these standards, however, was not based on
the maximum projections from performance assessments. More typically, compliance with
our release limits would be assessed using the mean value of projections, as it is at WIPP.
It is therefore difficult to directly compare the level of protection provided by the early
individual-protection standard and the later-term release standard.
Finally, it is also instructive to consider the very different approach taken in "Protection
Objectives for the Disposal of Radioactive Waste" developed by the Swiss Federal Nuclear
Safety Inspectorate (HSK) (HSK-R-21/e, November 1993, Docket EPA-HQ-OAR-2005-
0085-0055). Unlike the other examples discussed above, these guidelines contain no
provisions for the use of "complementary considerations" or "supplementary indicators" in
addition to individual dose or risk projections in determining whether the safety objectives
have been met, nor is there a time constraint beyond which the objectives do not apply.
There is, however, recognition that "[t]he further into the future predictions are, the greater
the uncertainty... dose calculations for the distant future are not to be interpreted as
effective predictions of radiation exposures of a defined population group. They are, in
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fact, much more in the nature of indicators for evaluating the impact of a potential release
of radionuclides into the biosphere" but are still compared to the specified limits (10
mrem/yr to what is essentially an average member of the critical group from "reasonably
expected" scenarios, with a risk from unlikely events not to exceed 10"6 per year). (Section
7.2) However, if a relatively small population would be affected, "the safety authorities
reserve the right to set the permissible dose lower than the limit specified." (Section 7.5)
We continue to believe it is appropriate to specify a higher peak dose standard applicable
between 10,000 years and 1 million years. We believe such an approach is consistent with
the NAS recommendations and is the most appropriate approach in view of the language in
the D.C. Circuit decision. The level we have selected for the peak dose standard, 100
mrem/yr, is consistent with the public dose limit recommended by ICRP and widely
adopted internationally and nationally, and we conclude that it will protect public health
and safety in the far future. Finally, we believe our interpretation of international guidance
and approaches regarding the application of performance assessments over very long time
frames is reasonable.
Section 4 Two-Tiered Standard
Issue B: Support use of a two-tiered standard
1.	EPA has correctly noted that very long-term risks are now managed, and must be
managed, differently from near-term risks, and thus we concur with EPA's decision
to apply a different standard after 10,000 years than it does before 10,000 years.
(Comment 0174-3)
2.	We support EPA's new two phase radiation standard for Yucca Mountain because it is
safe and realistic for the soon to be built nuclear storage facility. Clearly, we cannot what
know today what advanced technologies our future generations will come up with to
improve Yucca Mountain storage. Therefore, a different radiation standard for the "out
years" in the future makes good sense. The 2-tier radiation standard selected wisely by the
EPA is safe and fair. (Comment 0193-1)
3.	Because of uncertainties associated with the incredibly long compliance periods, having
a "two-tier" dose limit is justifiable. (Comment 0217-4)
4.	The Department believes an approach with two compliance periods to regulate
repository performance is appropriate because it embodies both good policy and good
science. The factors that would be applicable in demonstrating compliance during the two
periods, particularly uncertainty and its treatment, are sufficiently different that different
compliance standards are warranted for the 10,000-year regulatory period and the period to
time of peak dose. The 350 mrem/yr standard provides an acceptable level of protection
both today and in the far distant future. Retaining a 15 mrem/yr standard for the first
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10,000 years not only provides an acceptable level of protection but also ensures the use of
robust engineered barriers to ensure compliance with that standard during the first 10,000
years. These barriers will continue to operate, to some extent, throughout the million-year
period and, thus, keep exposure levels extremely low as long as possible. (Comment 0352-
16)
5.	While calculation of the performance of a repository system for a 10,000-year period is
complex, it is unarguably much more difficult to do that calculation for a period 100 times
longer with anything like the same degree of precision. Without specific guidance on how
to adopt appropriate bounding of potentially disruptive processes, extending the
performance assessment to the time of peak dose could introduce intractable speculation.
Accordingly, EPA has acted reasonably to develop two compliance periods and separate
calculational approaches for them. To do otherwise would ignore the limitations of
bounding analyses, the greater uncertainties at time of peak dose, and the lessened
precision in calculated results as time and uncertainties increase. (Comment 0352-17)
6.	We find the two-tiered dose limits for before and after 10,000 years to be an appropriate
recognition of the greater degree of uncertainty for the longer period. (Comment 0368.5-1)
Response to Issue B:
Several commenters agreed with our reasoning for applying different dose limits over
different time periods, specifically with regard to uncertainty in projections. Commenter
0352 believes "the factors that would be applicable in demonstrating compliance during the
two periods.. .are sufficiently different that different compliance standards are warranted"
and that the 15 mrem/yr standard for the first 10,000 years "ensures the use of robust
engineered barriers to ensure compliance with that standard." This commenter also states
that "[wjithout specific guidance on how to adopt appropriate bounding of potentially
disruptive processes, extending the performance assessment to the time of peak dose could
introduce intractable speculation" and that we have acted "reasonably" in proposing two
different compliance standards.
We agree with the commenters. It is our judgment that the uncertainties involved during
the unprecedented compliance period over which performance must be projected are
significant enough that an approach involving two individual-protection standards is
appropriate and, therefore, we have decided to retain it in the final rule. We are, therefore,
establishing 1 mSv/yr (100 mrem/yr) as the individual-protection standard applicable
beyond 10,000 years and up to 1 million years, which satisfies our EnPA mandate to
protect public health and safety and is consistent with the recommendation of the NAS
committee to establish a standard to assess compliance at the time of peak risk, within the
limits of geologic stability of the site. We are also retaining, however, the 150 [j,Sv/yr (15
mrem/yr) standard for the first 10,000 years, which is consistent with our overall risk
management policies and past practices, and serves as a reasonable transition point to the
projections of doses in the extreme far future. See Section 6 of this document for
discussion of issues related to uncertainty in performance assessment.
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Section 5 Risk Level
1.	EPA has now proposed to allow a highly dangerous and non-protective radiation
exposure standard of 350 millirems per year for the period after 10,000 years at Yucca
Mountain. Currently based on the NCRP recommendations, the cancer slope risk is about
6.4	x 10"4 latent cancer fatailities per rem. The actual slope from bomb survivor data is
twice this value or about 1.3 x 10"3 LCF/rem. The most recent and reliable retrospective
cohort study by Clemson University on DOE Hanford adult male workers shows a cancer
slope risk of about 1 x 10"2 LCF/Rem!!! This would mean that background radiation would
be expected to kill 17%-21% of the population. This is the vast majority of cancer deaths.
So to sum up, EPA's radiaiton protection standard for Yucca Mountain in particular and for
the all use in general should be changed to a single standard based on a 1 x 10"4 risk of
cancer through out all time periods, and that level should be assesed on a full 70 year life
span (neglecting only the last 5 years of life based on an inadequate time period to induce
cancer), and based on the most restrictive cancer slope data (the Clemson study at 1 x"2
LCF/rem) resulting in an allowable annual exposure limit of 0.14 millirem per year.
(Comment 0091-1)
2.	Using the standard 1 x 10"4 cancer fatality risk metric as the upper end of allowable risk
from any one source, and based on a 70 year expsoure, the radiation standard for added
exposure should be immediately reduced to 0.14 millirem/year. Even lacking the new
Clemson data and lacking a change in the exposure duration to reflect real lifetime
expsoures of 70 years, the EPA standard should be immediatley reduced to no more than
2.5	millirem per year. (Comment 0091-2)
3.	EPA's estimates there will be 10 million cancer deaths over 1 million years that result
from storing highly radioactive spent fuel in the mountain. (Comments 0103-5 and 0145-
5)
4.	EPA's proposal to allow 350 millirem per year radiation doses to people living
downstream from the leaking dump — the equivalent of 58 full chest x-rays per year —
would not only cause cancer, but also birth defects, genetic damage, and other maladies,
and at alarming rates, and must be withdrawn. EPA's proposed double standard must be
withdrawn. The proposal would protect people for the first 10,000 years to currently
applied standards of protection, but would then doom future generations after that time to a
1 in 36 cancer rate (or even worse, up to a 100% cancer rate, due to EPA mathematical
manipulation), and a 1 in 72 fatal cancer rate (or worse). Such proposed cancer rates and
fatal cancer rates are horrifying, and EPA must withdraw such an unacceptable proposal.
This is a complete violation of principles of inter-generational equity, as well as public
health and environmental protection. (Comments 0133-1, 0135-1, 0137-1, 0141-1, 0144-1,
0146-1, 0147-1, 0148-1, 0150-1, 0157-1, 0159-1, 0160-1, 0161-1, 0163-1, 0164-1, 0170-1,
0189-1, and 0190-1)
5.	Are you out of your minds? What you call an acceptable cancer risk is not acceptable at
all. (Comment 0154-1)
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6.	A candidate probabilistic safety goal for a repository would be that the latent cancer
fatality risk for the average individual located within the region of the repository would be
a small percentage of the average fatality risk (for today's population and 0.1% of the
annual health risk of death this implies a goal incremental risk < 1x10-5 per yr).
The appropriate size of the region should be based on the characteristic sizes of regions of
high background radiation and low background radiation that exist naturally today (on the
order of 100 to 500 miles). The smaller the region, the more conservative the criterion. In
applying the safety goal, the degree of confidence required would be determined by the
timeframe of the application. Thus, in the period of < 10,000 yr, a very conservative safety
goal could be established and compliance with the goal could be achieved at a degree of
confidence consistent with the mean value of the risk. In the period of >10,000 yr, a less
conservative safety goal could be established and compliance with the goal could be
achieved at a degree of confidence consistent with the median value of the risk. (Comment
0215-5)
7.	On August 3, 2005, the Institute for Energy and Environmental Research (IEER)
released a credible scientific report contending that EPA's federally allowed Maximum
Contaminant Level ("MCL") level of drinking water contamination by plutonium-239 and
other radioactive materials with similar properties is 100 times too high because it is based
on obsolete, 1950s science. Nevada's expert Dr. M. C. Thorne was one of the peer
reviewers of the study. The report, Bad to the Bone: Analysis of the Federal Maximum
Contaminant Levels for Plutonium-239 and Other Alpha-Emitting Transuranic
Radionuclides in Drinking Water, authored by Dr. Aijun Makhijani, president of IEER, is
attached as Appendix F to these comments. Since plutonium-239 is one of the long-term
risks posed by the Yucca repository, Nevada believes that the plutonium MCLs must be
revisited by EPA before permitting the proposed Yucca radiation standard to go into effect.
Plutonium and other alpha emitters will constitute the largest contributors to long term
radiation dose to humans from the repository. The IEER study bases its conclusion on well-
known advances over the past three decades in the scientific understanding of the behavior
in the body of plutonium and other alpha-emitting, long-lived transuranic radionuclides.
These radionuclides are now widely understood to concentrate near the bone surface and
deliver a dose per unit intake that is far higher than previously estimated by EPA. Yet, EPA
has thus far refrained from making more stringent its plutonium MCLs. (Comment 0226-
117)
8.	On page 3 of the document titled The Swedish Radiation Protection Institute's proposed
general guidance on application of the regulations concerning protection of human health
and the environment in the final management of spent nuclear fuel and nuclear waste (SSI
FS 1998:1), it is stated that the ICRP define the risk for the harmful effects per dose to
individuals from the population to be 7.3% per si evert. As 1 si evert is 100 rem, then this
risk is 7.3 x 10 "4 per rad. For the initial time period of 10,000 years the expected annual
dose can be as high as 15 millirem per year. This corresponds to a risk (from harmful
effects) of 1.1 x 10"5 per year. If the RMEI were to reside in the Amargosa Valley for 50
years, then the attendant expected lifetime risk is about 5 x 10"4 , i.e., one half of one tenth
of a percent. However, the proposed radiation standard after 10,000 years is 350 millirem
per year and is based on the median value of dose. So the proposed regulation increases the
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now median lifetime risk (i.e., the probability of exceeding this value is 0.5) is 1.3 xlO"2.
So the EPA considers it is being protective of health and wellbeing of future residents by
proposing regulations that at the 50% confidence level about one in every eighty people in
Amargosa Valley will die prematurely as a result of exposure to radioactive releases from
the facility. I believe such a level of protection would be totally unacceptable for present
day populations. When attention is focused on the mean value of dose (i.e., the expected
value), this risk value based on the median is increased by a factor about 32 to provide an
estimate of the expected lifetime (i.e., 50 year) risk of 0.4 - this means that almost half of
the population is expected to die prematurely from the radioactive releases from the
proposed repository. If the actual performance of the repository turned out to be at high end
of the predicted distribution of dose then the risk would be even higher, where we might
have four out every five of the population die prematurely from radiation exposure. Thus it
can be concluded that the EPA considers the proposed post 10,000 year radiation standard
to be protective of the health and safety of the future population when in reality it is
expected to cause the premature demise of 4 out of every 10 members of the local
population. It would appear the EPA is proposing to legislate in the favor of future
genocide in the Amargosa Valley and justify it as being politically acceptable. With
Federal Agencies looking after our wellbeing, who needs to worry about hurricanes, act of
terror, and weapons of mass destruction? [Note the ICRP are considering reducing the risk
value from 7.3% per sievert to 5.9% per sievert. However they are also considering
introducing a hereditary risk factor i.e., the risk posed to the second generation from
exposure of the parents.] (Comment 0263-19)
9. It appears that the USEPA not fully incorporate finding and conclusions of the National
Academy of Sciences report on Health Risks from Exposure to Low Levels of Ionizing
Radiation: BEIR VII report into their proposed new EPA radiation standard for YMP. The
consequences of this report include the concepts that that there is no safe level of exposure
to radiation—that even very low doses can cause cancer. Even exposure to background
radiation causes some cancer; additional exposures cause additional risks. The committee
also concluded that radiation can cause other health effects such as heart disease and stroke,
and that further study is needed to predict the doses that result in these non-cancer health
effects. The committee noted that it is possible that children born to parents that have been
exposed to radiation could be affected by those exposures. The committee also concluded
that risks from low dose radiation are equal to or greater than previously thought. However,
it should be noted that in populations that receive several times the natural background
dose or less, radiation is responsible for only a small fraction of the cases of cancer and
other health effects.. .The committee stated that the Dose and Dose-Rate Effectiveness
Factor which had been suggested in the 1990 BEIR V report to be applied at low doses, has
been reduced from 2 to 1.5. That means the current estimate of the number of health effects
at low doses is greater than the estimate used previously. This is extremely important since
it may have an effect on the EPA radiation standard for YMP of 15mRem effective dose.
While EPA used many times the phrase "calculated dose and or radiation," it is our opinion
that instead of using the above phrase there is a need for experimental data to verify
assumption used both by DOE and EPA. Finally, can the EPA provide recent experimental
data including possible radiation bystander effects to justify the 15 mRem effective dose
standard for YMP? (Comment 0270-5)
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10.	It is our opinion that the EPA should have taken a second look at epidemiology studies
at Chernobyl accident and Three Mille Island concerning cancer risk before issuing their
final radiation standard for YMP. (Comment 0270-8)
11.	In a comprehensive review of published data available for assessing the risk of
radiation induced cancer for radiation protection purposes, the UK Health Protection
Agency calculated the risk of radiation-induced cancer at low doses and low dose rates and
provided results of epidemiological investigations. The following is a short summary. 1.
"Studies of the effects of exposure to background radiation and of environmental exposure
are subject to the influence of confounding factors and generally lack sufficient statistical
power to detect small increases in risk." 2. Epidemiological studies thus indicate an
approximately 40% increase in the risk of radiation-induced cancer in childhood following
exposures in utero at doses of low-LET radiation of about 10-20 mGy. (Comment 0270-9)
12.	EPA does not discuss the increased risk to human health and safety from the higher
levels of exposure at the 10,000-year mark, despite the director of EPA's Office of
Radiation and Indoor Air's acknowledgement that the risk to public health increases at the
higher level. EPA does not assume that humans are somehow better able to handle doses
of radiation in the future. Rather, EPA admits that the 350 millirems number is not based
on public health, which is not EPA's concern. In an attempt to craft a standard that DOE
can meet rather than one based on sound science, EPA has ignored its most basic
responsibility, the protection of public health and safety. (Comment 0293-6)
13.	350 millirem per year over 70 years (EPA's standard assumed lifetime) is a cancer risk
of 1 in 36 (i.e., 2.8%). That is 288 times higher than EPA's outer limit of its acceptable risk
range (10"4) and 28,800 times higher than its preferred point in the risk range (10-6). Even
assuming only a 30 year exposure time - unreasonable in the scheme of things - yields a
risk of roughly 1 in 100, 100-10,000 times higher than EPA's acceptable risk range. These
figures are based on the National Academy of Sciences just-released BEIR VII report. The
BEIR reports, produced every decade or so, form the basis for all government risk
estimates; the Federal Guidance 13 estimates were derived largely from BEIR V. BEIR VII
increases risk estimates for cancer incidence by approximately third from the Federal
Guidance 13 levels. BEIR VII's new figure is 1.14 x 10"3 cancers per rem. (Comment
0296-2)
14.	For EPA to now propose a 350 millirem/year exposure limit, albeit for future
generations, is unconscionable and vastly outside what even the current EPA rules suggest
is dangerous to public health. A dose of 350 millirem/year over one's lifetime, according to
the recent National Academy of Sciences report on radiation risks, will cause cancer in
approximately one out of every 36 people exposed. This is vastly outside the l-in-10,000 to
1-in-a-million risk range EPA has used as a basis for establishing radiation exposure limits.
(Comment 0301-3)
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15.	EPA's general position for decades has been to regulate exposures to keep the risk to
the public at one cancer in one million people. In some circumstances, EPA has allowed
workers to be exposed to a higher risk of cancer - one in one thousand. According to a
recent National Academy of Sciences report on radiation health risks, 350 millirems per
year over one's lifetime will cause cancer in approximately one out of every 36 people
exposed—a risk 3 to 5 orders of magnitude greater than the range that EPA has always
used before. (Comment 0302-13)
16.	Under the EPA's rule, there is no upper limit of dose for the half of the exposures that
would be above the median. In other words, under the EPA standards, significant numbers
of people could legally be exposed to doses that would produce a statistical 100% chance
of inducing a cancer in the exposed individuals. (Comment 0302-15)
17.	We are opposed to your proposed standard of 350 millirem/year radiation exposure of
the public downstream of the proposed Yucca Mountain high-level radioactive waste site in
Nevada after the first 10, 000 years. The numbers of cancers, congenital and genetic effects
that would result for future generations are totally unacceptable from the standpoint of
public health and environmental health protection, as well as ordinary morality. This
proposed rule equates to premeditated murder and must be withdrawn. (Comment 0308-1)
18.	The proposed peak dose limit would pose a lifetime cancer incidence risk of 1 in 36 for
the general population and 1 in 30 for women. EPA has previously stated that even 1 in 250
lifetime risk is unacceptable from a single facility. (Comment 0314.1-5)
19.	The 350 millirem per year dose limit is 14 times higher than the dose limit contained in
NRC regulations governing the disposal of low-level radioactive waste and more than
twenty times higher than the dose limit previously proposed by the EPA as being protective
of the public health (i.e. 15 millirem per year). Using the risk factors from the National
Academy of Sciences BEIR VII report, we find that the excess cancer risk for an individual
that would be exposed to 350 millirem per year over a 70 year lifetime would be more than
1 in 36. The risk to women from this level of exposure would be even greater,
approximately 1 in 30. These risks are unacceptably high. As discussed in section three
below, the EPA's choice of the median dose for determining compliance with the 350
millirem per year dose limit means that the upper bound doses actually received could be
significantly higher. (Comment 0314.1-9)
20.	The higher level radiation standard may seriously impact the health of Las Vegas'
citizens. NAS's recommended acceptable range of radiation exposure, which the EPA
previously recognized, is 2 to 20 millirem per year . The level of human exposure after
10,000 years permitted by the new rule far exceeds this range. This higher level will
result in additional cancer deaths over time. In fact, the State of Nevada's health and
safety consultant concludes that exposure to a 350 millirem additional annual dose for
just three years would create a 4.8 percent increase in cancer risk. (Comment 0341-2)
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21.	It is unfortunate NAS did not have available the deliberations of.. .NAPA... The
principles developed by NAPA suggest that when looking exceedingly far into the future,
the major concern should be to avoid the possibility of catastrophic consequences. Basing
the level of protection at time of peak dose on consequences that would be catastrophic in a
global sense in the context of events over the course of one million years, or at least
catastrophic on a regional or even individual level, would require consideration of the
levels at which health effects from radiation have been actually observed. In the proposed
rule, EPA noted: "The BEIR [Biological Effects of Ionizing Radiation] VII report
reaffirmed that evidence exists that even the smallest radiation dose may convey some risk
of incurring a cancer, and the risk increases proportionally to the dose...." The Department
believes that this does not correctly reflect the conclusions of the BEIR VII study. The
study cited no evidence proving actual effects at small doses. Furthermore, the study
considered 100 mSv (10 rem) to be "low dose." This is not "the smallest radiation dose," or
even a small dose, by regulatory standards. The study's conclusion was that "...current
scientific evidence is consistent with the hypothesis that there is a linear, no-threshold
dose-response relationship between exposure to ionizing radiation and the development of
cancer in humans." Neither did the study find that "evidence exists" that risk increases
proportionally to dose. The report states: "The Committee judges that the balance of
evidence from epidemiologic, animal and mechanistic studies tend to favor a simple
proportionate relationship at low doses between radiation dose and cancer risk.
Uncertainties on this judgment are recognized and noted." The statement of considerations
for EPA's final rule should reflect that the BEIR VII report reaffirmed the appropriateness
of assuming, for regulatory purposes, that small radiation doses may convey some risk of
incurring cancer, and that risk increases proportionally to dose, while recognizing
uncertainties with this assumption. (Comment 0352-22)
22.	Has EPA done the calculations to estimate occurrences of cancer due to exposure from
Yucca Mountain? (Comment 0367.1-6)
23.	What is the standard of what is safe for my body - today or in the future? (Comment
0367.1-12)
24.	We strongly oppose EPA's proposal. ... double standard .. extremely dangerous and it
is immoral. These proposed regulations are completely unacceptable and should be
immediately withdrawn. For the first 10,000 years, people exposed to ... a lifetime cancer
rate of one in 835 people. Then it dooms future generations to a new radiation standard of
one in 36 cancer rate	 This is a complete violation of EPA's responsibility to protect
public health and the environment. A standard based on a one in 36 cancer rate is not a
standard. It is a death sentence. This proposal to allow 350 millirem per year radiation
doses to people living downstream ... would cause cancers, birth defects, and genetic
damage. (Comment 0368.1-1)
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25.1 really urge you to do that (consider BEIR VII) because it's quite different from the
BEIR 5 report in many important respects that I'm sure you already know. The risks to
children are shown to be much greater than the risks to grown-ups. The risks to women are
shown to be overall much greater than men. For the first time, cancer incidence risks have
been published and I believe you should go according to cancer incidence risks and protect
to standards like one in 10,000 for cancer incidence, not cancer fatalities because fatality
rates are changing all the time, fortunately coming down due to improved medicine. Now,
I think that the question of protecting pregnant women should also be part, the question of
protecting developing fetuses and embryo. (Comments 0368.3-8 and 0368.4-3)
26. EPA's general position for decades has been to regulate exposures to keep the risk to
the public at one cancer in one million people. According to the recent BEIR 7 report on
radiation health risks, 350 millirems per year over one's lifetime will cause cancer in
approximately one out of 36 people exposed. This is a risk three to five orders of
magnitude greater than the range the EPA has always used before. (Comment 0368.6-4)
Response to Section 5:
Many of the commenters in this section have made reference to the risk estimates that EPA
uses for assessing the impacts of radiation exposure. The comments were generally
phrased in relation to the proposed peak dose standard of 3.5 mSv/yr (350 mrem/yr). We
are not establishing the proposed 350 mrem/yr level as our final peak dose standard;
instead, we are establishing 1 mSv/yr (100 mrem/yr) as the standard to apply for the period
beyond 10,000 years and up to 1 million years. Because the comments addressed
fundamental issues involved in estimating risks from radiation exposure, however, we are
responding to the comments on this topic.
Comment 0091-1 supports a lifetime risk-based standard at 10"4and refers to a study of
workers at DOE's Hanford facility showing that the risk of radiation-induced cancer may
be 50 times higher than current EPA estimates. Our Yucca Mountain standards are dose-
based at the direction of Congress. We are unfamiliar with the study cited by this
commenter (which was neither submitted nor adequately referenced), but find the
suggested risk coefficients to be implausible and contradicted by the current body of peer-
reviewed epidemiological studies of radiation workers, as summarized in Chapter 8 of the
BEIR VII report (Docket No. EPA-HQ-OAR-2005-0083-0430).
Comment 0091-1 also says, "Currently based on the NCRP recommendations, the cancer
slope risk is about 6.4 x 10"4 latent cancer fatalities per rem. The actual slope from bomb
survivor data is twice this value or about 1.3 x 10"3 LCF/rem." Our adjustments to its risk
coefficients account for increased repair at low doses and dose rates. Our understanding of
radiogenic cancer risk relies heavily on the ongoing studies of the Japanese atomic bomb
survivors. Because the doses that this group received occurred over a very short time
period, an adjustment to the Japanese data is commonly made when using the Japanese data
to estimate the risk from radiation exposure at lower doses and dose rates. (See BEIR VII,
Docket No. EPA-HQ-OAR-2005-0083-0430, Chapter 6, for discussion of Japanese
survivor studies.) The 1993 report by the United Nations Scientific Committee on the
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Effects of Atomic Radiation, Sources and Effects of Ionizing Radiation (Docket No. EPA-
HQ-OAR-2005-0083-0406), and the 1994 EPA report, Estimating Radiogenic Cancer
Risks (Docket No. EPA-HQ-OAR-2005-0083-0405), have recommended a dose and dose
rate effectiveness factor (DDREF) of 2 when acute doses are less than 20 rem and the dose
rate is less than 10 mrem per minute. The commenter is suggesting that it is inappropriate
for us to apply a DDREF to our estimates of cancer mortality risk at Yucca Mountain
because the total doses from the site will also be high dose exposures. In fact, releases
from Yucca Mountain resulting in an RMEI dose at the peak dose limit of 100 mrem/yr
would easily meet the criteria for applying the DDREF. We believe that it is appropriate to
continue to apply a DDREF of 2 for its cancer risk coefficients, as described on pages 173-
174 of Federal Guidance Report 13 (Docket No. EPA-HQ-OAR-2005-0083-0072).
Comment 0091-2 recommends that the dose limit for Yucca Mountain should be 0.14
millirems per year for any time period, cited as the results of a Clemson University study of
DOE Hanford workers (see above response to 0091-1), or no more than 2.5 mrem/yr, based
on a 1 in 10,000 risk limit for 70 years of exposure using current risk estimates. These
suggested dose limits are below any dose-based limits currently in force in the United
States today. The farther out in time the analyses go, the more uncertainty there is in the
dose projections. Restricting doses in the extreme far future to levels that are well below
what are regulated today would be unreasonable.
Comments 0103-5 and 0145-5 say that EPA estimates 10 million cancer deaths from Yucca
Mountain over 1 million years. There is no reference given for this assertion, but it is
perhaps a reflection of another comment (0324-5) that references the following language
from our 1985 final rulemaking for 40 CFR Part 191 that "estimates of the risks from
unmined ore bodies ranged from about 10 to more than 100,000 excess cancer deaths over
10,000 years. Thus, leaving the ore unmined appears to present a risk to future generations
comparable to the risks from disposal of wastes covered by these standards" (50 FR 38083,
September 19, 1985, Docket No. EPA-HQ-OAR-2005-0083-0064). Comment 0324-5
then makes the erroneous assumption that the upper end of this estimate (10 excess cancer
deaths per year world-wide) equates to what EPA would consider an acceptable risk for
releases from Yucca Mountain over each of the next one million years. Comment 0324-5
is also addressed in Section 3, Issue F, of this document. All these comments are based
upon a misreading of EPA's text and are incorrect. The release limits in 40 CFR Part 191
were scaled to a level estimated to result in 1,000 excess fatal cancers over 10,000 years
from disposal of 100,000 metric tons of heavy metal. The individual peak dose standard is
not based upon or related to the risks from uranium ore bodies. Our role at Yucca
Mountain is to establish public health and safety standards with which DOE must
demonstrate compliance.
Comments 0133-1, 0135-1, 0137-1, 0141-1, 0144-1, 0146-1, 0147-1, 0148-1, 0150-1,
0157-1, 0159-1, 0160-1, 0161-1, 0163-1, 0164-1, 0170-1, 0189-1, 0190-1, 0154-1, 0263-
19, 0293-6, 0296-2, 0301-3, 0302-13, 0302-15, 0308-1, 0314.1-5, 0314.1-9, 0341-2,
0368.1-1, and 0368.6-4 state, in various ways, an opposition to the risks from radiation
exposure at 3.5 mSv per year and many of them reference a 1 in 36 risk of excess cancer at
this exposure level. Using a conversion factor of 5.75 x 10"7 fatal cancers per mrem, our
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final long-term peak dose standard of 1 mSv/yr (100 mrem/yr) represents a nominal annual
risk of fatal cancer of 5.75 x 10"5, or 5.75 in 100,000. This is comparable to the range of
risks represented by domestic and international regulations thatNAS suggested EPA
consider, and which NAS stated were "consistent with recommendations from authoritative
radiation protection bodies" (Comments 0196-1 and 0198-4 appear to refer to the low end
of the NAS suggested starting range in their references to "one in a million per year").
(NAS Report p. 49 and Tables 2-3 and 2-4) EPA does not consider this level of risk to be
excessive in the context of a standard applicable for the period from 10,000 years to 1
million years, given the increased uncertainty in dose projections and the questionable
assumption that current risk estimates can be applied to the extreme far future. Risk
correlations at any time cannot be considered absolute and precise, particularly when
applied in a prospective manner to the behavior of a disposal system that will operate
passively for hundreds of thousands of years (we note that NAS applied a smaller
conversion factor of 5 x 10"7 fatal cancers per mrem). When time frames on the order of 1
million years are considered, it is reasonable to view the nominal risk associated with the
100 mrem/yr peak dose standard as a reasonable level of risk. We are focusing discussion
of the risk associated with the peak dose standard on annual risk, as this was the metric
considered appropriate by the NAS committee, although it did not recommend a particular
risk level. The Agency has determined that this standard will protect public health and
safety. Comment 0341-2, referring to a State of Nevada consultant's report, claims that
exposure to 3.5 mSv/yr for 3 years would result in a 4.8% increase in the cancer rate. This
statement is unfounded and seems to be a misinterpretation of the Nevada consultant's
statement [Appendix A, Mike Thorne and Associates Limited, External Memorandum,
page 7, Docket No. EPA-HQ-OAR-2005-0083-0227] that exposures at 3 times this level
(i.e., 10.5 mSv/yr) over a lifetime would increase a person's risk of cancer by 4.8 %. It is
important to note that these estimates of cancer incidence relate to the proposed dose
standard. Our 100 mrem/yr standard applies only to the hypothetical reasonably maximally
exposed individual, who is defined to be among the most highly exposed members of the
population.
Comment 0215-5 discusses the relationship of the safety goal for Yucca Mountain with the
degree of confidence in the target risk value, stating that "In the period of >10,000 yr, a less
conservative safety goal could be established and compliance with the goal could be
achieved at a degree of confidence consistent with the median value of the risk." We have
set the peak dose standard at a level higher than for the first 10,000 years in part because of
the uncertainties involved in projecting doses in the far future. Our final standards include
both a more stringent peak dose standard and specification of the arithmetic mean as the
statistical measure of compliance.
Comment 0226-117 presented information and an assessment of health effects and risk
estimates for ingestion of an isotope of plutonium. While this comment may have potential
relevance to risk assessment in general, we believe that this level of detail is outside the
scope of comments since it pertains to the ground-water protection standards which are not
part of the amendments to 40 CFR part 197. The information mentioned in this comment is
more relevant and could be considered in the context of the periodic re-examination of
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dose/risk factors for specific radionuclides by the scientific radiation risk assessment
community.
Comments 0270-5, 0368.3-8, and 0368.4-3 encourage EPA to implement the findings and
recommendations of the recently released BEIR VII report. In fact, it will take us the next
few years to incorporate the BEIR VII recommendations and make necessary updates to its
risk assessment methodology. However, the overall risk estimates of the BEIR VII
Committee are compatible with our current risk estimates. One notable change in the BEIR
VII report is the recommended value for the dose and dose rate effectiveness factor
(DDREF). The DDREF is used to adjust the slope of the observed dose response curve at
high acute doses when extrapolating down to the low dose and low dose rate region of
interest. The BEIR committee recommended a change in the DDREF from 2 to 1.5.
However, ICRP's most recent recommendations still support using a value of 2.
(Publication 103, Docket No. EPA-HQ-OAR-2005-0083-0423) Both organizations
acknowledge that the range of experimentally observed DDREF values makes its selection
a matter of judgment. Therefore, the value of the DDREF is still an unsettled issue, and we
will continue to follow the debate on this issue.
Comment 0270-8 encourages EPA to take a second look at the results from
epidemiological studies of populations exposed from the Chernobyl accident and from the
accident at Three Mile Island. We do not believe there is any evidence of increased cancer
incidence from the Three Mile Island accident, which had very low off-site doses. Current
epidemiology shows a significant and increasing risk of thyroid cancer among those
exposed as children from the Chernobyl accident. Reports of anecdotal, but as yet not
statistically significant increases in other cancers among responders and other highly
exposed groups are being followed closely by EPA. However, at present, the Chernobyl
data and our risk estimates are consistent, so we see no need to change our estimates, but
would do so if significant increases were noted. See the 2003-2005 report of the Chernobyl
Forum, Docket No. EPA-HQ-OAR-2005-0083-0419.
Comment 0270-9 quotes some findings of the UK Health Protection Agency regarding (1)
the inability of epidemiological studies to detect small increases in risk as a result of
variations in background, and (2) the increased risk of cancer in children following in utero
exposures of 10 to 20 milligray (mGy). We consider the peer-reviewed scientific literature,
such as the data reported here, when assessing changes to its risk assessment methodology.
We agree with the statement about variations in background. However, doses in the range
of 10 - 20 mGy (1-2 rad) are much higher than our long-term dose rate limit. We believe
that the in utero doses from Yucca Mountain releases, even at the level of our peak dose
standard, will fall within the current safe guidelines for exposure of the fetus as
recommended by the ICRP and NCRP (ICRP Publication 60 (Docket No. EPA-HQ-OAR-
2005-0083-0421) and NCRP Report 116 (Docket No. EPA-HQ-OAR-2005-0083-0407),
respectively). The same study was referred to by Comment 0226-5 in Section 2, Issue H of
this document.
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Comment 0352-22 takes issue with how EPA characterized the BEIR VII report's
recommendation regarding the application of a linear dose response relationship at low to
very low doses. The commenter encourages us to be more explicit about the uncertainty
associated with this assumption and to make it clear that the linear dose model is a
regulatory tool. We will examine our representation of the uncertainties surrounding the
dose response curve at low doses, but overall, we stand by our interpretation of the BEIR
VII recommendations that they were unequivocal in their support for using a linear no-
threshold model.
Comment 0367.1-6 asks if EPA has calculated the excess cancers from exposure to Yucca
Mountain. We have not calculated projected excess cancers because our authority and role
is solely to set the public health standards; it is DOE that has the authority and role to
project potential doses resulting from the performance of the Yucca Mountain disposal
system. However, as noted above, using our current cancer risk coefficients, we estimate
that members of a population who receive an extra 100 mrem/yr would have an additional
annual cancer mortality risk of 5.75 x 10"5, or 5.75 in 100,000. This is comparable to the
range of risks represented by domestic and international regulations thatNAS suggested
EPA consider.
Comment 0367.1-12 asks what a safe level of radiation is today or in the future. What is
"safe" is very much an individual value judgment, but we believe that our final standards
are protective of the residents living near the Yucca Mountain site now and in the extreme
far future. Using our current risk estimates, potential radioactive releases in the extreme far
future will present a 4 x 10"3 risk of fatal cancer (0.4%) above the current baseline risk of
22% for the projected RMEI, assuming a dose rate of 100 mrem/yr for 70 years.
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Section 6 Uncertainty
Issue A: Higher uncertainty should not be addressed by using a higher dose limit
1.	EPA's proposed rule offers no reasonable basis for diverging from the NAS's
recommendation and from its own past practice, or for using one compliance measure for
the pre-10,000-year period and another for the post-10,000-year period. Primarily, EPA
cites uncertainties about Yucca Mountain and perceived "over-conservatisms" in DOE's
modeling. These uncertainties and supposed over-conservatisms, EPA claims, call into
question the higher values in DOE's modeling, and suggest that a performance measure that
devalues those higher values is appropriate. These explanations lack any logic or
rationality. [Uncertainty provides no reason for creating a more lax standard, whether that
laxity is achieved through a higher numeric standard or a more permissive statistical
measure. Similarly, conservatism provides no reason for selecting the median rather than
the mean, because conservatism, if it actually existed (the reverse is the case), would be a
reason for DOE to fix its modeling, not for EPA to adjust its standard. (Comment 0226-15)
2.	Moreover, it defies logic and common sense to use uncertainty about Yucca's future
performance as a rationale for a looser standard. If DOE is highly uncertain about whether
its chosen site and systems will be safe, that uncertainty provides more reason for retaining
a conservative, protective standard through peak dose, not a looser one. (Comment 0226-
24)
3.	Even if EPA were correct that Yucca's long-term performance after 10,000 years is
qualitatively more uncertain, its proposed rule fails to explain how that uncertainty justifies
a more lax standard. (Comment 0226-26)
4.	Such an explanation would be extraordinarily difficult to provide, for the reasonable
response to uncertainty about the safety of an engineered system would be to demand
greater protection, or preclude that system from being deployed at all. Reasonable
regulators never would evaluate the safety of bridges, for example, against less stringent
safety standards simply because engineers were able to predict their performance only over
the short-term. That uncertainty should only make regulators more conservative, not less.
(Comment 0226-27)
5.	Consistent with that principle, EPA (and other federal agencies) have until now reacted
to anticipated uncertainty by adopting conservative assumptions and standards. In fact,
Nevada has confirmed that, when faced with uncertainty, EPA uses conservative
assumptions and adopts conservative standards in all areas of health-based regulation
except, now, for Yucca. EPA does not explain why it departs from these sensible
precedents. (Comment 0226-28)
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6.	For example, EPA adopted conservative values of parameters or standards when there
were uncertainties when it regulated underground injection of hazardous materials under a
regulatory regime (40 C.F.R .Part 148, especially 40 C.F.R. § 148.21(a)(5)) requiring that
there be no migration of the wastes for so long as they remain hazardous, 69 Fed. Reg.
15328 (March 25, 2004); when it developed a methodology for deriving air quality criteria
to protect health, 65 Fed. Reg. 66444 (November 3, 2000); when it regulated pesticides to
protect health, 64 Fed. Reg. 37022 (July 8, 1999) ("the greater uncertainty in the data
associated with the assumptions, the more conservative (i.e., unlikely to underestimate
exposure) the assumptions should be"), and 68 Fed. Reg. 15945, April 2, 2003
("uncertainty was addressed in the screening level assessments.. .with conservative
assumptions for model inputs"); when it increased the cover standards to limit emissions
from uranium mill tailings because of uncertainty in long-term (1000 year) projections, 48
Fed. Reg. 45926 (October 7, 1983); when it set water quality standards for toxic pollutants,
64 Fed. Reg. 61182 (November 9, 1999); when it developed a policy regarding persistent,
bio-accumulation of new chemicals, 64 Fed. Reg. 60194 (November 4, 1999) ("given.. .the
uncertainty... due to lack of data, the TSCA new chemicals program is and must be
conservative by nature"); when it set emission standards for locomotives and locomotive
engines, 63 Fed. Reg. 18978 (May 14, 1998); when it adopted principles for estimating
neuro-toxicity in risk assessments, 59 Fed. Reg. 43260 (August 17, 1994); when it
regulated hazardous wastes using the 90th percentile Monte Carlo risk curve, 63 Fed. Reg.
42110 (August 6, 1998); when it regulated food additives, 56 Fed. Reg. 7750 (February 25,
1991) ("in addressing uncertainties [in quantitative risk assessment] however, EPA
generally uses conservative assumptions to ensure that risks are not underestimated.");
when it protected drinking water, 56 Fed. Reg. 3526 (January 30, 1991); and when it listed
hazardous wastes under RCRA, 55 Fed. Reg. 11798 (March 29, 1990).
Other federal agencies use similar approaches. For example, OSHA used the 95th
percentile (as opposed to the central tendency) value in risk assessments used to derive
safety standards for workers' exposure to toxic chemicals, 62 Fed. Reg. 1494 (January 10,
1997) (standards for methylene chloride). And HHS uses conservatisms in addressing
health effects, 61 Fed. Reg. 33511 (June 27, 1996) ("a conservative (i.e., protective)
approach to address these uncertainties in health effects"). (Comment 0226-29)
7.	While EPA repeatedly emphasizes "uncertainty" as a core justification for its proposed
rule, its discussions of uncertainty are hopelessly vague. EPA uses the term "uncertainties"
generically. It rarely specifies either the particular uncertainties with which it is actually
concerned, or their likely effects, and it never coherently explains how it believes specific
types of uncertainty might justify a more lax or a two-tiered standard. This is especially
important when one considers that the most obvious source of potential uncertainty, climate
change, as well as others, are eliminated from consideration. This is a crucial failure. It
precludes Nevada and others from knowing which uncertainty sources EPA considers
important, and why EPA believes those sources might justify a higher standard. Indeed,
EPA's failure to specify the relevant uncertainties suggests that EPA may not even know
which uncertainties matter, or what the implications of particular sources of uncertainty
actually are. Indeed, as noted earlier, premising a rule on uncertainties in the licensing
analysis before the licensing analysis is even done is itself speculative to the point of being
useless. (Comment 0226-31)
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8.	The reason you offer, that uncertainties allow such a large limit is simply outrageous.
You claim to be protective by increasing the allowable doses just because there's more
uncertainty in predicting releases. That doesn't give you a justification for increasing the
dose limit. Quite to the contrary, if there's such great uncertainty you should have stricter
limits or at least the same limits as before - not raise the limits because you're afraid that
you can't meet them. If you can't meet them then the Yucca Mountain dumpsite is simply
unsuitable. (Comment 0260-1)
9.	EPA claims that "rising uncertainties justify adopting a different (higher) dose level"
after 10,000 years. But in its study, NAS concluded that the uncertainty for one million
years is manageable because of the known geologic processes affecting the site, clearly
contradicting EPA's statements. Thus, EPA's reasoning for increasing the dose after
10,000 years is not substantiated. (Comment 0302-8)
10.	EPA holds that "the rationale for the 350 additional millirem from 10,000 years and,
beyond deals with the amount of uncertainty that we're faced with in projecting out 10,000
years ..." This is a quote from an Associated Press article dated October 10, 2005,
attributed to EPA, spokesman John Millett. My simple question is, if uncertainty increases
over time, shouldn't the regulations be strengthened, not weakened, to accommodate for
that?! EPA seems, in its proposed rule, to largely think that "conservatism" is a bad or dirty
word. When it comes to protecting human health and human lives and the environment, the
most conservative, protective standards need to be applied. (Comment 0324-13)
11.	EPA states in column 1, page 49021, that "realistic analyses are preferred over
conservative and bounding assumptions, to the extent practicable." But how "realistic" can
federal agencies be when predicting out 10,000 or 1,000,000 years into the future?
Not being conservative in this case is an, unacceptable retreat, and sacrifices the public's
right to health and environmental protections from the one agency in the federal
government charged with that mandate, the EPA. EPA states on page 49025, column 1 that
"it is 'reasonable' to consider approaches for uncertainties in calculations at several hundred
thousand years that may differ from the approach for uncertainties considered within
10,000 years after disposal...". By weakening the regulations?! Shouldn't EPA
STRENGTHEN the regulations, given such large uncertainties and the long-lasting
deadliness and hazard of high-level radioactive wastes? Such uncertainties require MORE
conservatism, not less! (Comments 0324-20, 0324-22, 0324-26, and 0324-30)
12.	Currently, the general consensus of national and international scientific community is
that radiation doses above background should not exceed 100 mrem/yr effective dose for
continuous or frequent exposure from radiation sources other than medical exposures. In
the U.S., the accepted apportionment for radioactive waste management is 15 mrem/yr
This, 15 mrem/yr, all pathway and the Safe Drinking Water Standard have been deemed by
our society as the allowed dose (risk). While Citizen Alert would like to see more stringent
standards, at the very least, these should be upheld through the period of peak risk;
otherwise, the integrity of the EPA will be undermined. How are we to know when the
EPA is developing a sound scientifically protective standard or just bending to special
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interests? Relaxing the standard to accommodate greater uncertainties is not justifiable, and
outside of the responsibility of the EPA. The preamble contends that since the results of
performance assessment past 10,000 years are highly uncertain and that a higher allowed
dose limit is necessary to satisfy a "reasonable expectation" of the goals of the standard.
The REASONABLE EXPECTATION is that the EPA will act as an independent agency
and advance protection standards that do just that, "... protect human health and the
environment." It is not the role of the EPA to cater to the "needs" of the Dept. of Energy
(DOE) to have a standard that will a priori allow Yucca Mountain to be licensed.
(Comment 0328-9)
13. Uncertainty does not justify the application of different levels of protection. (Comment
0368.10-2)
Response to Issue A:
A number of comments stated that uncertainty did not justify a two tiered standard
(Comments 0226-15, 0226-31, and 0368.10-2), or an apparent relaxation of the 15
mrem/yr standard (Comments 0226-24, 0226-26, 0260-1, and 0324-13), and in fact
uncertainty should lead to tighter standards (Comments 0226-24, 0324-20, 0324-22, 0324-
26,	and 0324-30) or even the elimination of the Yucca Mountain site as a potential geologic
repository (Comment 0260-1). Some comments stated there was no, or insufficient,
rationale connecting questions of uncertainty and dose limits (Comments 0226-26, 0226-
27,	0226-28, 0226-31, and 0302-8). Similar points are touched on in Section 2 of this
document, Issue F. We also refer readers to Section 18, where we address comments on
the related topics of implementability and reasonable expectation.
We do not agree with these comments for several reasons. Making dose projections for a
geologic repository over the time frames involved - upwards of 1 million years - requires
the extrapolation of information about the characteristics of the site and the performance of
the engineered and natural barriers well beyond the ranges of practical experience with
these materials. Significant uncertainties are involved and unavoidable when projecting the
expected performance of any potential deep geologic repository to such time frames, and
these uncertainties must be considered in setting standards and judging compliance
assessments against such standards. NAS also "recognize[d] that there are significant
uncertainties in the supporting calculations and that the uncertainties increase as the time at
which peak risk occurs increases." (NAS Report p. 56) These uncertainties, and the ability
of the performance assessment techniques to distinguish between credible alternative
models of the disposal system performance, represent the scientific limits of the technology
to make projections of future performance.
In setting standards for the 10,000-year period, EPA believes that uncertainties in
projecting performance are more manageable than at much later times, i.e., over the 1
million-year period of geologic stability. While NAS recommended that safety
assessments be performed over the period of geologic stability and expressed its belief that
bounding analyses were possible as a way to manage longer-term uncertainties, the
committee made no recommendations about risk limits for compliance decisions. Rather, it
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acknowledged that such decisions should be made in the public rulemaking process. We
believe that these very long-term assessments can be made, but we also believe that
quantitative safety assessments should not be the only factor when making regulatory
decisions for these very long time frames, and that the limitations of such assessments
should be considered in setting a standard. We believe its frequent references to
"bounding" approaches indicates a recognition by NAS that there are inherent uncertainties
in characterizing the disposal system that cannot be eliminated, i.e., limits to the ability of
the technology to make definitive "predictions" of disposal system performance in the very
long term. This reasoning is the basis for having a two-tiered standard: an "early" time
frame standard when uncertainty is relatively low that is consistent with established
practice for regulating geologic disposal systems, and a later time frame standard when the
confidence in quantitative assessments is unavoidably lower (Comments 0226-15, 0226-31,
and 0368.10-2,), as explained further below.
We see a changing role for quantitative safety assessment as the compliance period is
extended from 10,000 years to as long as 1 million years. Initially, greater confidence can
be placed in the characterization of the site and other components of the disposal system,
and the idea that site evidence from the relatively recent past (thousands of years) can be
used to support near-term projections (10,000 years). When looking farther out in time (as
long as 1 million years), however, confidence in the individual factors affecting
performance and their interplay will be lessened as the disposal system evolves from its
original state in ways that are not entirely predictable from a knowledge of current
conditions at the site. By extension, confidence in dose projections from that evolving
system will also be lessened. At all times, a regulator should have confidence that an
applicant has sufficient understanding of the system and the factors affecting its
performance. Numerical projections for comparison with specific criteria are not the only
way, or always the best way, to demonstrate such understanding. The joint IAEA-NEA
Peer Review of the Total System Performance Assessment - Site Recommendation (TSPA-
SR, Docket No. EPA-HQ-OAR-2005-0083-0062, pp. 23-24) addressed this point directly:
[T]he IRT has observed a tendency for more focus to be given to the demonstration
of numerical compliance with the proposed regulatory requirements than on
developing and presenting an understanding of repository performance.. .In this
regard, there is an emerging international consensus that building confidence in
repository performance is of comparable importance to demonstrating compliance
with criteria.
For periods on the order of 10,000 years, there is a body of experience in conducting and
interpreting assessments of dose and risk, such that greater reliance can be placed on them
to demonstrate system understanding. Conservatisms can be more easily identified and
quantified, and sensitivities and uncertainties can be more easily bounded and their
influences examined. At much longer times, however, when the system has evolved from
its initial conditions, the methods and assumptions used to construct the assessment take on
greater significance, since the site's characteristics and the processes operative under these
changed conditions, are more uncertain. In our view, it would be reasonable to give less
weight to peak dose assessment results when considering overall system safety, as
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compared to assessments covering the initial 10,000 years. Extending the same dose limit
throughout the period of geologic stability would not adequately recognize this shift over
time. (66 FR 32098, June 13, 2001, Docket No. EPA-HQ-OAR-2005-0083-0042)
The approach we have included in our final rule is to specify a dose standard for the initial
10,000 years, as well as a second, higher, dose standard for the time of peak dose beyond
10,000 years. The context for these two standards in the rule is identical. Each must be
met for NRC to issue a license. However, we believe a higher peak dose standard is an
appropriate and effective way to address the concerns outlined above regarding the use of
projections at very long times. DOE's peak dose projections will be examined in detail in
the licensing review. While making its licensing decision, we do not believe that NRC will
focus on just the projected doses. Rather, NRC will consider a number of factors in
determining whether there is a reasonable expectation that the standard will be met (e.g.,
Docket No. EPA-HQ-OAR-2005-0083-0376, p. 45). DOE will be required to explain and
defend its assumptions, data, and methods. We see a higher standard as providing the
appropriate recognition of the limitations in performance projections over very long time
periods and encouraging a more thorough exploration of the implications of changes in the
assumptions, data, and methods, as well as the role of conservatism and uncertainty in
constructing robust assessments. For these reasons, we do not believe the approach
suggested by commenters to incorporate more conservatism or rely on bounding
approaches is appropriate. (Comments 0226-28, 29, and 0324-20, 0324-22, 0324-26, and
0324-30)
Our conclusion that a higher peak dose standard is appropriate does not directly tell us what
that standard should be. One thing is clear, however, whatever the standard is, it must be
protective of public health and safety. We believe that data used in quantitative safety
assessments becomes more uncertain as time progresses. The characteristics of the site will
vary over time as a consequence of natural processes at and around the site, which are
occurring at different rates. As a result, the performance of the natural barrier components
have associated uncertainties, both in defining their characteristics as they may vary over
very long timeframes and in projecting their combined effects on performance. Similarly,
the engineered barriers will inevitably degrade and also change the characteristics of the
natural barriers around the wastes. Degradation of the engineered barriers involves
multiple elements, each with its own failure mechanisms and rates. The drip shields and
double-layered metal containers would fail from various corrosion mechanisms, whose
presence or absence and rates will vary as the physical and chemical conditions in the
emplacement drifts vary over time. The cladding around the fuel pellets could fail by
different mechanisms and rates (stress induced failures, corrosion processes) than the drip
shields and container. Finally, the fuel pellets themselves will undergo degradation that
will vary as functions of the age of the pellets and the chemical environment surrounding
them before and after the containers are breached and ground water enters. Thus,
degradation of the natural and engineered barriers results in the release of radionuclides in
ways that are not completely predictable quantitatively. While considering how our peak
dose standard might appropriately reflect these uncertainties, we turned to two sources of
insight, approaches used in other disposal programs and our own technical assessments.
(Docket Nos. EPA-HQ-OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-0429)
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The international radioactive waste community has grappled with the question of
increasing uncertainty and the use of quantitative safety assessments in regulatory decision
making. As discussed in the preamble to the proposed and final rules, international
organizations and disposal programs abroad have suggested that exposure levels in the very
long-term in the range of background radiation levels could be considered acceptable. As
discussed in the preamble for the final rule, we have set a 100 mrem/yr peak dose limit
during the stability period, rather than the limit in the proposed standard. The rationale for
this selection is also discussed in Section 3 of this document.
Our approach for the extreme far future differs from the international practice primarily in
that we are establishing an explicit, numerical peak dose standard against which assessment
results will be compared, whereas the preferred approach internationally is to emphasize
other non-quantitative factors influential to safety. In that approach, numeric assessment
results are considered more for what they indicate about overall performance rather than
their strict conformity with specific dose or risk criteria.
The second approach we have used is our own technical analyses. EPA has done some
technical modeling studies of the site to examine the implications of the very long time
frame for the geologic stability period on the reference dose limit of 10,000 years proposed
in the standard. (Docket No. EPA-HQ-OAR-2005-0083-0386) This dose limit is the only
established and implemented marker for acceptable repository performance. It was
established in 40 CFR part 191 on a generic basis for any disposal system, and
implemented for the WIPP facility certification. As such it represents the level of exposure
the society is willing to accept as acceptable health risk from a deep geologic repository for
a 10,000-year period. Our technical analysis examines the propagation of uncertainty as
reflected in dose projections over the very long-term and estimates the variations in doses
that could result for a hypothetical disposal system under the conditions at Yucca
Mountain. To do this analysis, we constructed a hypothetical situation where the number
of failed waste packages necessary to deliver a mean dose of 15 mrem/yr at Yucca
Mountain dose was calculated, and then the release projections from this fixed number of
packages was followed to peak dose, under the range of conditions expected for the site.
The resulting peak doses calculated were in the range of several hundred mrem/yr at peak
dose, for various approaches to the computer simulations. The analyses looked at the
effects of uncertainty, as reflected by the spread in site data used in the modeling, on the
very long-term performance of this hypothetical system. It should be understood that this
represents a hypothetical disposal system and is not intended to represent the actual
expected performance of the site, since we deliberately constructed a disposal system that
was at the "edge of compliance" at 10,000 years, i.e., it was set to produce a mean dose of
15 mrem/yr at 10,000 years. Results of the analyses showed that the uncertainty (reflected
by the difference between the 5th and 95th percentiles of the calculated doses) from the
initial starting point, the "edge-of-compliance" hypothetical system at 10,000 years, and at
peak dose, increased by approximately two orders of magnitude. The uncertainties
reflected in these results concern the behavior of the natural barrier over time relative to the
hypothetical "edge-of-compliance" disposal system examined. These results support our
position that uncertainties in projecting doses into the very long-term do increase
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significantly. The increasing spread in dose projections limits the ability of numerical
performance assessments to distinguish between possible alternative assumptions and
conceptual models that could be proposed for the disposal system, and makes performance
assessments in the very long-term a less reliable tool for projecting doses with confidence.
We also examined uncertainties and alternate conceptual models of how the disposal
system's performance is assessed, both in terms of the engineered and natural barriers
(Docket Nos. EPA-HQ-OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-0429). The
results in these documents illustrate the complicated interplay between uncertainties in the
natural and engineered barrier performance and the decreasing ability of the performance
assessment tool to distinguish between alternative conceptual models that produce dose
estimates within the observed limits of data and model uncertainties. Consequently our
assessments show that less confidence can be placed on the results of such very long-term
projections in compliance decision-making, as highly confident "predictions" of
performance into the very long-term. The decreasing confidence on the reliability of
numerical dose projections over very long time frames is supported by these analyses, and
supports our decision to look to other contexts as a framework for selecting a peak dose
limit.
We believe, considering the results of our modeling, that the peak dose standard should not
be viewed as a less strict or "loosened" standard, but rather as reasonable (Comments 0226-
24, 0226-26, 0260-1, and 0324-13). Moreover, as established elsewhere, the peak dose
standard is protective of public health and safety. See Sections 2 and 10 of this document
for additional discussion of the protectiveness of the peak dose limit. We have established
standards that are protective of public health and the environment, meaningful,
implementable, and provide a reasonable test of the disposal system that is consistent with
the NAS Report, D.C. Circuit decision, and the principles of reasonable expectation. In our
view, an unchanging 15 mrem/yr standard would not present a reasonable test and would
not be appropriate (Comments 0226-24, 0324-20, 0324-22, 0324-26, and 0324-30).
Comment 0226-15 mentioned that uncertainty is not a reason for changing the standard but
rather for DOE to fix its modeling, while other comments claimed that uncertainty
affecting the peak dose standard argues for rejecting the site (Comment 0260-1). As
described above, the peak dose limit for the period of geologic stability appropriately
recognizes the limitations of modeling over very long times and is reasonable and
protective of public health. The implications of the standards for DOE's modeling is a
question for DOE to address relative to its modeling efforts and the licensing process.
Final licensing or denial of a license is the purview of the NRC (Comment 0260-1).
Comment 0226-27 likened setting two dose standards for different times as akin to setting
two different engineering standards for a bridge on the basis of uncertainty. The comment
questioned why, in the light of uncertainties over long time periods, a stricter standard for
later times was not the more appropriate course of action to compensate for uncertainties.
While this analogy is appealing on the surface, it fails to capture the substantial difference
between the two situations. A bridge can and would be maintained through its entire
functional lifetime, in contrast to the disposal system at Yucca Mountain which is intended
to be a passive system, i.e., it must perform as expected without human intervention over
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the compliance period. Over long time periods at Yucca Mountain, the engineered barriers
will inevitably degrade and uncertainties about the slower evolution of the natural barrier
around the repository cannot be eliminated. Therefore in the very long-term, the
confidence that can be placed in performance projections must inevitably decrease. We
recognized this in selecting a peak dose limit higher than the 15 mrem/yr limit for 10,000
years, but which is still a protective limit for the reasons explained elsewhere in this
document and the preamble to the final rule. For the bridge and repository situations to be
analogous, one would have to assume that the bridge receives no maintenance over an
equivalent functional lifetime (hundreds of thousands of years). Assigning the same
performance expectations to an un-maintained bridge over such a time span, or even a few
decades, would not be reasonable.
Comment 0226-29 presents a long list of references to other regulatory actions involving
some degree of uncertainty, lack of applicable data, and conservative assumptions, taken by
the regulatory agencies in response to these situations. These cited examples are
fundamentally different from the case of deep geologic disposal of radioactive wastes. The
cited examples concern areas where institutional controls are assumed to operate to monitor
and address adverse effects, collect necessary information to improve health effects
assessments as necessary, and thereby assess the impact of "conservative" assumptions
taken in prior regulatory decisions. For deep geologic disposal, the intent of the effort is to
develop a system that will perform acceptably without the need for human intervention.
Indeed, with consideration of the time frames over which the disposal system operates (as
long as 1 million years under the regulatory framework), it must be assumed that the
operative time frame is far too long to assume that any active institutional controls can
operate. For the disposal system, uncertainties must be identified and assessed during the
operational period prior to repository closure, and regulatory decisions made using that
understanding. In contrast to the examples posed by the comment, we believe that
uncertainties should be reflected in a cautious, but reasonable, approach to setting the
standard, so that a protective standard can be developed and regulatory decisions made
with full knowledge of the inherent uncertainties in the disposal system affecting such
decisions.
Section 6 Uncertainty
Issue B: Recognizing the uncertainties is reasonable
1. Protecting people and the environment is one responsibility, balancing risk is another. To
base a judgment about a repository's level of protection in comparison to natural exposure
levels demonstrates a healthy level of rationality. The uncertainties in projecting repository
performance out to 1,000,000 years are such that modeling can not really show that release
limits of a few 10s of millirems are met and that to pretend it can is ridiculous on its face.
The EPA has proposed a radiation exposure limit in the period beyond 10,000 years that is
not so low that it flat out dooms Yucca Mountain to failure. A rationale that compensates
geologic uncertainty with a larger exposure limit is responsible. (Comment 0185-2)
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Response to Issue B:
We agree with the thrust of this comment (Comment 0185-2), in terms of the risk
management approach we have used in setting the peak dose standard, and the degree of
confidence that can be placed on quantitative dose projections in the very long-term. We
believe that the standards we have set are a responsible balancing of risk and public health
protection, and recognize the limits of confidence in quantitative modeling over the
geologic stability period as reliable predictions of potential exposures.
Section 6 Uncertainty
Issue C: General uncertainty comments
1. The Supplementary Information contains many discussions to the effect that
uncertainties in projecting the performance of waste disposal systems increase with
increasing time. Other reports by the IAEA and NEA, for example, are cited to support this
assertion. It may be true that uncertainties generally increase with increasing time in the far
future. However, it must be understood that assertions about this in IAEA and NEA reports
are based on an important assumption, namely that uncertainties in future biospheres and
human behaviors are important factors in determining uncertainties in projected doses at far
future times. IAEA and NEA reports have assumed that future biospheres and human
behaviors are largely unknown and that their uncertainties are largely unquantifiable.
What I am asking here is that EPA consider revising its discussions of uncertainties and
how they change over time to properly account for assumptions that are implicit in
discussions of this issue in other reports but are not relevant to EPA's regulations, given
that the biosphere and human behaviors at future times are fixed by rule at Yucca
Mountain. EPA should also consider whether an assumption that uncertainties increase
with time is reasonable at Yucca Mountain. (Comment 0186-15)
2.1 would also note that it may not be true that uncertainties in projected doses at Yucca
Mountain increase with time out to one million years. It seems to me that uncertainties are
likely to be largest during the period when waste containers fail and the uncertainty in the
distribution of container failures over time is likely to be an important contributor to the
overall uncertainty in projected doses. Once all containers have failed, it seems to me that
uncertainties will decrease even though projected doses are increasing. I also note that, as
indicated in the Supplementary Information, this perspective on when uncertainties are the
greatest was presented in the NAS report on Technical Bases for Yucca Mountain
Standards (Docket No. OAR-2005-0083-0076). EPA's arguments to dismiss the point of
view in the NAS report are unpersuasive. I am also not persuaded by EPA's arguments on
this issue in Section II.C .2 of the Supplementary Information. (Comment 0186-17)
3. A different perspective on the important issue of uncertainty that I believe is more
relevant, ... is this. The important issue is not whether uncertainties in projected doses
increase with time over one million years (or, at least to the time of peak annual dose).
Rather, the important issue is that the uncertainty in whether the Yucca Mountain facility
will be in compliance with standards clearly increases out to the time of peak annual dose
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(and perhaps beyond, if projected annual doses are not decreasing substantially with time).
That is, the issue is one of uncertainty in regulatory decision making, not uncertainty in
projected doses, although the two are linked. For example, large uncertainties in projected
doses are unimportant if upper credibility limits are well below applicable dose criteria.
(Comment 0186-18)
4.	You talk a lot about uncertainties. And that really is quite a smoke screen. There is not
that much uncertainty. Department of Energy has done computer simulations, they show us
what they expect doses to be. And they're right out there within that range. And you've met
what their expectations are by having the median used for your calculation mark and by
having 350 millirem. (Comment 0209.14-6)
5.	The core justification EPA offers for numerous components of its proposed rule—its lax,
two-tiered standard; its use of the median rather than the mean; and its attempts to pre-set
modeling parameters, among others—is increased "uncertainty" after 10,000 years. But the
EPA and DOE studies relied on by EPA show no qualitative increase in uncertainty after
10,000 years, and there is good reason to believe that the uncertainty after 10,000 years will
in fact be less. Therefore, uncertainty provides no foundation for EPA's proposed rule. This
contention is set forth in great detail in a report prepared for Nevada by Dr. M. C. Thorne,
The Role of Uncertainties in Defining the Proposed Standard (Nov. 10, 2005), attached as
Appendix C. Moreover, as the Court has already pointed out, EPA's uncertainty rationale
is inconsistent with the NAS's findings and recommendations. (Comment 0226-23)
6.	EPA's discussion of uncertainty is terminally vague, and fails to specify not only the
logical link between uncertainty and a looser standard but also the types of uncertainty
upon which EPA bases its logical leaps. Had EPA actually considered specific sources of
uncertainty, it would have found that no source provides a basis for rationalizing a looser
standard. (Comment 0226-25)
7.	In fact, EPA's abandonment of its longstanding approach to uncertainty has the effect of
protecting humans in Nevada less than fish, for NOAA used conservative assumptions
when confronted with uncertainty in protecting fish populations, 59 Fed. Reg. 7647
(February 16, 1994); 57 Fed. Reg. 3952 (February 3, 1992). (Comment 0226-30)
8.	Just as the Army Corps of Engineers should not measure levees against lax safety
standards because it cannot predict exactly when Katrina-esque hurricanes will strike,
Yucca Mountain should not be held to a looser standard simply because DOE cannot
project when exactly the engineered barriers will fail. They will fail, and radionuclides will
escape, at some time. EPA's standard must protect against that threat even if EPA and DOE
are uncertain whether it will occur in 400 or 400,000 years. The particular sources and
types of uncertainty that exist at Yucca Mountain do have implications for regulatory
decision-making. Some uncertainties imply that the site should be more carefully studied.
Others imply the need for better engineering, or for a different site. None of these types of
uncertainty provide any basis for a looser standard, or for taking a different approach to
assessing post-10,000-year compliance. The report by Dr. Thorne [Appendix C] establishes
this fact. On a regulatory policy level, uncertainty about potential flaws in DOE's
engineering barriers provides a reason for demanding better-engineered systems or, perhaps
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more realistically, for locating a site where geologic systems provide containment and thus
mitigate the impact of the engineered barriers' inevitable failure, as is the case with DOE's
WIPP repository site, for example. But it defies logic to suggest that DOE is entitled to a
looser safety standard because it cannot say for certain whether its engineered systems will
work. (Comment 0226-32)
9.	The NAS was clear that reasonable predictions of the performance of the natural systems
can be made within the period of geologic stability. But here too, DOE is not entitled to a
looser safety standard simply because it is uncertain how its chosen site will behave
because it stopped its site investigation program before all of the data were in. Also, some
natural systems at the site will change in the future—for example, climate will vary,
earthquakes may occur, and volcanic eruptions may disrupt the repository—and some
uncertainties do exist with respect to such changes. The NAS considered possible
uncertainties in natural system behavior and specifically concluded that they did not
preclude assessments of performance at peak dose. It repeatedly rejected any suggestion
that these parameters change and become more unpredictable at 10,000 years, noting that
"earth scientists are accustomed to dealing with physical phenomena over long time
scales." Id. at 71. But again, such uncertainties, even if they were more than NAS assessed,
are no basis for setting a laxer standard. If Yucca were a better site, with much longer
geologic containment, these uncertainties would matter much less or not at all. A poor site
is no justification for a lax standard. (Comment 0226-33)
10.	The NAS noted one specific restriction on that conclusion—its determination that
future human scenarios were too uncertain to model—but otherwise adhered to the
consistent conclusion that uncertainties did not preclude meaningful assessments of long-
term compliance with a numeric standard. Id. And it expressly rejected any suggestion that
10,000 years represents a significant crossover point at which uncertainties render long-
term compliance assessment less meaningful, finding that "there is no scientific basis for
limiting the time period of an individual-risk standard in this way." Id. at 6. The NAS
report thus contains an unequivocal rejection of the notion that uncertainties are somehow
more unmanageable in longer-term compliance projections. (Comment 0226-34)
11.	In addition to being inconsistent with the findings and recommendations of the NAS,
EPA's conclusions about steadily increasing uncertainty are wrong. Even if DOE is correct
in its optimistic assumptions about short-term performance of the waste canisters, its
current modeling graphs indicate that the range of modeling results rises initially but then
decreases as time passes. See Appendix C. And if those engineering assumptions are
acknowledged to be major sources of uncertainty, the highest levels of uncertainty are
likely to occur even earlier. (Comment 0226-36)
12.	Rather than acknowledging, let alone avoiding, this conflict, EPA attempts to mask it
through disingenuous discussion of the NAS report. EPA quotes the NAS stating,
"[bjecause there is a continuing increase in uncertainty," and suggests that this carefully
selected excerpt indicates that the NAS clearly agrees with EPA's view that "uncertainties
generally increase with time, at least to the time of peak dose." 70 Fed. Reg. at 49025. But
the entire NAS quote states: "Because there is a continuing increase in uncertainty about
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most of the parameters describing the repository system farther in the distant future, it
might be expected that compliance of the repository in the near term could be assessed with
more confidence. This is not necessarily true." NAS Report at 72 (emphasis added). The
NAS then explained why "this is not necessarily true," pointing out that many site
parameters (like geologic parameters) do not change with time, and that others are more
significant during the short term. Id. (Comment 0226-37)
13.	EPA's FEPs also undermine the key rationales for EPA's creation of a higher numeric
standard in the post-10,000 year period, and for EPA's position shift to require use of the
median, rather than the mean, for projecting compliance. EPA proposes to justify both its
350 millirem/year standard and its use of the median primarily on the rationale that both are
necessary to manage long-term uncertainties in performance assessment. EPA's theory
appears to be that a combination of uncertainty and compounding conservative assumptions
will unavoidably skew DOE's modeling, and that, rather than expecting DOE to fix those
perceived modeling problems, EPA must for some reason compensate for that skewing by
using a commensurately skewed higher standard and a less conservative statistical
compliance measure. The use of predetermined FEPs undercuts EPA's uncertainty
rationale. By specifically defining future states for crucial FEPs, such future climate states,
EPA manages uncertainty out of the modeling process. Having taken that step, it is
inconsistent to optimistically adjust the end-goal to account for negative uncertainties that
the modelers have been required to remove. Essentially, this methodology double-counts
the perceived uncertainty. The use of FEPs also thoroughly undercuts EPA's
predetermination that DOE's modeling process will be overly conservative. As shown in
the mathematical example above, arbitrary exclusion of FEPs can inherently skew the
modeling process toward optimistic outcomes. (Comment 0226-95)
14.	In the proposed regulations the EPA discusses uncertainty in predicted performance,
especially the speculated increase in uncertainty after 10,000 years. However, each of the
physical and chemical processes occurring in the release and transport of radionuclides is
not particularly complicated especially once the thermal excursion, due to the heat of
radioactive decay, has passed. There are uncertainties associated with many of the
parameters required to numerically generate a solution to the defined set of release and
transport equations. These uncertainties are quantified by using the techniques of
probabilistic risk assessment where they provide a predicted distribution of results. This
expected distribution, which includes the composite effect of all uncertainties considered, is
compared to the proposed standard to establish whether or not a reasonable degree of
compliance has been achieved. If the distribution of predicted results becomes
unacceptably wide (or skewed) as the simulation time increases then it is fair to infer that
either the performance of the repository is unacceptable or our understanding and modeling
of the processes governing performance are unacceptable. In the case of the latter
eventuality, if we cannot reasonably predict repository performance with some acceptable
confidence at all times, we have no right to place waste in Yucca Mountain. (Comment
0263-1)
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15.	If the proposed regulation is to specify how compliance will be assessed, then the
method must be applied in a consistent and logical manner to the probabilistic predictions
of repository performance. As long term performance has not been predicted in recent
years by DOE, the EPA's (a priori) approach must be meaningful for all combinations of
performance results. The EPA position of stating that there is very large uncertainty at late
time has no basis and is speculation. Two examples of potential suites of results are
discussed. The EPA's final methodology must allow sound regulatory decision making on
both of these stylized examples. (Comment 0263-12)
16.	EPA concludes that current activities constitute the least arbitrary scenario to use in
calculating human exposures, but when confronted with a similar type of uncertainty in
modeling geologic conditions, EPA concludes that at a certain point the uncertainties of the
analyses eliminate credibility altogether, but fails to state why 10,000 is the magic dividing
line. (Comment 0311.1-11)
17.	The standard should recognize that the uncertainties in the estimated doses will increase
with time and that the uncertainties beyond 10,000 years will become very significant. In
this regard, therefore, we propose that the EPA adopt the French approach to waste
repository standards in which the doses beyond 10,000 years are calculated using
scientifically reasonable, but highly conservative choices for the important parameter
values in order to increase confidence that the ultimate impacts from the repository will be
less than those predicted. (Comment 0314.1-8)
18.	EPA goes on "Such a conclusion would be inconsistent with any concept of permanent
disposal, which necessarily requires examination of time frames and events that cannot be
predicted with certainty,". This is not true. Yucca's geology is fractured and fissured and
entirely unsuitable for high-level radioactive waste burial. But other geologic settings
within the United States could very well be much more geologically stable and reliable for
radiation isolation than Yucca's earthquake-plagued volcanic tuff EPA should not paint
Yucca critics as complete nay-sayers to geologic disposal. This is an unfair and inaccurate
characterization. (Comment 0324-31)
19.	Emphasis on "long time" misleading - issue is how well DOE understands the site.
(Comment 0367.1-17)
20.	There is too much uncertainty involved in ensuring the facility can meet its limits.
(Comment 0367.2-26)
Response to Issue C:
A number of comments made reference to the NAS statements about uncertainty possibly
decreasing over very long time frames and being potentially more manageable than at
earlier times (Comments 0186-17, 0226-33, 0226-34, 0226-36, and 0226-37). NAS made
statements that it believed uncertainties would increase for some aspects of the site but that
these uncertainties were boundable within the geologic stability period. We agree with this
assessment, but offered cautions in our writing that bounding analyses could become overly
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conservative in terms of the assumptions used with the net effect that the actual expected
performance of the site could be poorly represented by overly "pessimistic" assessments.
A number of comments stated that our approach to integrating uncertainty considerations
into the proposed standards conflicts with the NAS positions on the role of uncertainties in
setting standards (Comments 0186-17, 0226-23, 0226-33, 0226-34, 0226-36, and 0226-37),
differs from other approaches to uncertainty in regulatory matters (Comment 0226-30), or
is too vague on the subject of uncertainty and regulatory decision making (Comments
0226-25 and 0263-12). We believe our approach does take proper account of uncertainties
as NAS suggested. Comment 0226-37 takes issue with our excerpt of a statement by NAS
regarding "continuing increase in uncertainty," implying that we have removed it from its
context and disregarded the remainder of the statement. We note that the entire statement
is included in the preceding paragraph (70 FR 49025). The commenter is correct that our
basic position agrees with NAS that "uncertainties generally increase with time, at least to
the time of peak dose." The committee stated that position directly in discussing its
recommendation for a peak risk standard: "We recognize that there are significant
uncertainties in the supporting calculations and that the uncertainties increase as the time at
which peak risk occurs increases." (NAS Report p. 56) We agree with this general
statement because the Earth is not a static system and over time changes in the natural
barrier around Yucca Mountain should be expected.
The NAS also pointed out that some major uncertainties, specifically those arising from the
degradation of the engineered barrier components, would decrease after these barriers
degrade to the point of ineffectiveness, and in some respects that could make projections of
very long-term performance less uncertain than projections when the engineered barriers
are actively degrading and releases occurring as functions of how the barriers fail and at
what rate, particularly if this occurs during the early thermal pulse period when short-lived
radionuclides decay and generate considerable heat. Comments 0186-17 and 0226-36 did
not find persuasive our argument that this tends to downplay the uncertainties in one of the
more significant factors in the timing and magnitude of peak dose. Overall, we agree that
system uncertainty would be less if the engineered barriers were intended to provide
containment for only a few thousand years, rather than function for tens to hundreds of
thousands of years. However, although the assessment may be bracketed by periods of
relative certainty in the behavior of the engineered barrier (initially, all containers and
barriers are intact; at some later point, none or very few are), the assessment results reflect
the period of relatively rapid change in between, when waste packages are failing not only
across time but spatially within the repository. From very long time periods the gradual
evolution of the characteristics of the natural barrier add uncertainty to dose projections
using characteristics defined by present-day conditions.
Regarding the "manageability" of long-term uncertainty, NAS also made the point that it
believed uncertainties could be addressed by bounding analyses. We disagree with
commenters who interpret such statements as "rejecting" the idea that uncertainties, and
their impact on assessments, become more problematic to evaluate over time. NAS
emphasized that its recommendations were scientific in nature. The committee recognized
that "the objective instead is a reasonable level of confidence in analyses" and "the level of
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confidence for some predictions might decrease with time." (NAS Report p. 71) The
committee further emphasized the policy aspects involved, such as the standard itself, the
compliance period, and what would constitute a "reasonable level of confidence" in
analyses. We believe that NAS recognized that performance assessments would effectively
become more stylized as the assessment period increased (as a result of using bounding
assumptions to address some uncertainties that prove difficult or impossible to define more
precisely), and that this is reflected in its frequent references to "bounding" approaches as a
way to manage uncertainties in making compliance assessment "feasible." (NAS Report p.
55) Thus, while Comments 0226-33 and 0226-34 are correct that NAS made no specific
statements regarding 10,000 years in this regard, we believe it recognized that a compliance
standard applicable for periods approaching 1 million years might differ in some ways from
its recommendations.
On the role of bounding assessments, we have been more cautious, as described in our
preamble to the proposed standards (70 FR 49042). We believe that bounding analyses
have value, but it can be compromised if the analyses are excessively conservative in terms
of both the assumptions in the analyses and the spread of parameter values chosen for the
analyses. While conservative assumptions commonly used in bounding analyses are to be
expected, and a degree of conservatism is desirable, we cautioned against putting heavy
reliance on assessments that contain many, and perhaps extreme, conservative assumptions
for bounding assessments. Such overly conservative analyses tend to present an
unnecessarily pessimistic picture of performance, and can mask a lack of understanding of
how the site will actually function. Neither of these alternatives is desirable. To the latter
point, we agree with part of the statements in Comments 0226-32 and 0367-17 that
uncertainties should be reasons for more investigation of the site to lower uncertainties
where it is practical and productive to do so with additional studies. However, we also
recognize that the impetus for more studies in any particular area to lower uncertainties
should be balanced against the overall uncertainties in projecting performance of the
disposal system as a whole, so that resources are targeted to lower uncertainties associated
with significant factors determining long-term performance and dose estimates.
To assess the uncertainty in projecting performance over the period of geologic stability,
we have performed some limited site-specific modeling, examining the range of parameter
values projected for the site as described in our supporting documents (Docket No. EPA-
HQ-OAR-2005-0083-0386, EPA-HQ-OAR-2005-0083-0414, and EPA-HQ-OAR-2005-
0083-0429). The modeling work is described in detail in these documents, and
summarized below as it relates to the comments. To examine the question of increasing
uncertainty over very long time periods, it is necessary to begin the analyses from a well
defined starting point. The starting point for our analyses is a hypothetical disposal system,
functioning at the "edge-of-compliance" at 10,000 years, i.e., we used the simplified site
model described in this report to determine how many waste packages to fail within 10,000
years (under the assumptions of the analyses which differ from the actual expected
performance of the Yucca Mountain repository design) to produce a mean dose of 15
mrem/yr at 10,000 years as the reference case (Docket No. EPA-HQ-OAR-2005-0083-
0386). This reference case also reflected the uncertainty in natural barrier performance for
the period up to 10,000 years in defining the mean dose to the RMEI. We then continued
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the analyses out to projections of peak dose and examined the growth of uncertainty in the
dose projections, as illustrated by the spread between the 5th and 95th percentile values of
the projected doses, without allowing any additional waste package failures to contribute to
doses (i.e., no additional radionuclide inventory was introduced after 10,000 years into the
disposal system modeled). With this model construction we were examining the effects of
uncertainties in calculating the natural barrier performance contribution to estimates of the
peak dose projections for the hypothetical disposal system we addressed. As a matter of
definition for our unique analyses, we considered the engineered barriers to be the metallic
waste containers, the spent fuel cladding and the drips shields. Without eliminating
additional waste package failures from contributing to releases, we would not be able to
isolate the effects of natural barrier uncertainties (from whatever source, e.g., uncertainties
in laboratory measurements or field tests) on the calculated dose projections from
uncertainties due to the engineered barrier performance. The spread in dose projections for
the peak dose estimates in these calculations increased approximately two orders of
magnitude relative to the reference case at 10,000 years, illustrating a quantitative increase
of uncertainty over the long-term. It should be noted that these calculations are relevant to
the reference case we defined. Other conceptual models for the disposal system, involving
other assumptions, would give different results, potentially with less or greater changes in
the range of calculated dose projections. The intent of our analyses was to assess the
relative changes in dose projections for a defined disposal system over the time to peak
dose, as an illustrative example of the uncertainty levels in the dose projections for
relatively short (10,000 years) and long time periods (to peak dose). This objective was
focused primarily on addressing the questions of whether uncertainties could be shown to
increase over very long periods out to peak dose, and we believe that our analyses show
this for the natural barrier portion of the disposal system.
We also examined uncertainties in both the natural and engineered barrier performance to
identify processes that play a dominant role in the peak dose calculations and examine their
likely behavior over long time frames and the ability of performance assessments to
distinguish between alternative conceptualizations of the disposal system. (Docket Nos.
EPA-HQ-OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-0429) Our conclusions
indicate that performance assessments have limitations in distinguishing between
alternative conceptualizations where the peak doses differ by tens of mrem/yr, and that
uncertainties in the rates and magnitude of some processes can produce divergent results
under some conditions. For example, differences in corrosion rate assumptions can
produce dramatic differences in peak dose values, but assumptions about roof fall in the
emplacement drifts and the consequent intrusion of ground waters can have marked effects
on peak dose, either increasing or decreasing it significantly. These general observations
indicate that uncertainties, and the assumptions used in modeling, over the very long time
frames involved in assessments have an important role in the assessment results and the
degree of confidence that can be placed in them as reliable projections of future behavior.
Comment 0209.14-6 expressed an opinion that uncertainties are not large. We disagree
with the comment. These analyses support our premise that uncertainties in making dose
projections over very long time frames limits and lessens the degree of reliance that can be
placed on these numerical assessments for regulatory decision-making, both in terms of
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setting standards and making compliance decisions against standards. The effect on
regulatory decision making of increasing uncertainties over time lies in the problem of
being able to meaningfully distinguish among alternative assumptions about the behavior
or characteristics of components of the disposal system and their effects on dose
projections. We have also examined engineered and natural barrier uncertainties and
alternative conceptualizations of the disposal system on dose projections to gain insight on
how these issues affect the confidence that can be placed on dose projections. The effects
of different assumptions about the behavior of specific processes, or changing site
characteristics, for example, can easily be overwhelmed by increasing uncertainties in the
disposal system performance as a whole. In our modeling we see that different corrosion
rate assumptions for the waste packages can lead to dramatic changes in the time and
magnitude of the peak dose (an engineered barrier uncertainty). However assumptions
about the extent of roof collapse can also dramatically affect the peak dose estimates,
illustrating the complex interplay of processes involved in natural barrier and engineered
barrier performance. The results of our assessments show that as uncertainties increase in
the long-term, therefore, the ability of dose projections to critically distinguish between
alternative representations of the disposal system in numerical models diminishes, under
the larger envelope of uncertainties in performance of the total integrated disposal system.
As our analyses show, the long-term uncertainties in calculating the natural barrier
performance increase significantly over time, supporting our rationale for considering other
strategies for setting the peak dose limit, as explained in the preamble to the final rule and
other places in this document. (Docket Nos. EPA-HQ-OAR-2005-0083-0414 and EPA-
HQ-OAR-2005-0083-0429)
We agree with the comments that stated the most uncertain time is when the repository
engineered barriers are breaking down. Indeed, this is the most complex period for
realistically quantitatively describing the performance of the disposal system. However,
this is also the period when doses are moving upward from minute levels to higher levels.
After the engineered barriers have degraded sufficiently that their containment capabilities
are largely gone, the radionuclide inventory within the waste packages is obviously far
more accessible for transport out of the repository and into the natural barrier.
Uncertainties in the natural barrier at that time would play a more significant role
quantitatively in dose projections than they would when the engineered barrier is still
providing significant containment. Our uncertainty analyses addressed the growth of
uncertainties in the natural barrier for the hypothetical limited-inventory system we
modeled during the time when the natural barrier performance is most important.
Comment 0226-36 refers to DOE dose projections rising with time as the engineered
barrier degrades and a decrease with time thereafter. This decrease at long times is due to
radionuclide decay in the waste packages creating a lower radionuclide inventory after they
are breached rather than a decrease in uncertainties in the very long term. DOE dose
projections show an approximately two order of magnitude spread in dose estimates during
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this post-peak time frame (when most of the waste packages have been breached and are
releasing radionuclides). This corresponds with the two order of magnitude increased
spread of dose assessments relative to the reference case in our modeling for the
hypothetical disposal system with a fixed number of failed waste packages (Docket No.
EPA-HQ-OAR-2005-0083-0386).
Our assessments were used to examine the range of uncertainty in site conditions and
parameter values, and in this way we believe we have considered uncertainties in setting
the standards as the NAS intended. That is, we have considered the potential effects of
uncertainties and the limitations they impose on the confidence that can be placed on very
long-term dose projections as well as the ability of performance assessments to
meaningfully distinguish between alternate conceptualizations of the disposal system. We
believe these analyses provide a quantitative means of describing increasing uncertainty in
projecting doses over the period of geologic stability. We believe the peak dose limit we
have established is protective and provides a reasonable test of the disposal system
performance, appropriately considering the uncertainties that exist for the site (Comments
0226-32, 0226-33, and 0367.2-26). See the discussion in Issue A of this section for more
details on this technical work.
Comment 0186-15 suggests that our discussion of international positions on uncertainty is
misleading because we do not highlight the fact that much of this uncertainty is related to
biosphere and human behavior assumptions (Comment 0226-34 makes a similar point in
connection with the NAS recommendations). The commenter believes we have
significantly reduced, if not eliminated, this source of uncertainty by specifying
characteristics of the RMEI. The commenter points out that "IAEA and NEA reports have
assumed that future biospheres and human behaviors are largely unknown and that their
uncertainties are largely unquantifiable." We acknowledge the commenter's point, and
agree that the inability to project human behavior as far into the future as some other
factors is a significant source of uncertainty, but do not believe it affects our position
regarding uncertainty in dose assessments. The NAS committee stressed the impossibility
of predicting future human behavior and recommended that we should define a receptor
consistent with current population patterns and lifestyles (NAS Report p. 122). We believe
this approach is generally consistent with the growing acceptance internationally of the
concept of "reference biospheres." For example, the IAEA has made this suggestion, but
recognizes that such assumptions create a more stylized calculation: "While it may be
possible to make general predictions about geological conditions, the range of possible
biospheric conditions and human behaviour is too wide to allow reliable modelling. The
emphasis of assessment should therefore be changed so that the calculations relating to the
near-surface zone and human activity are simplified by assuming present day communities
under present conditions. Such calculations can therefore only be viewed as illustrative
and the 'doses' as indicative. The use of reference biospheres will likely become a principal
tool in this time frame." ("Safety Indicators in Different Time Frames for the Safety
Assessment of Underground Radioactive Waste Repositories," TECDOC-767, 1994,
Docket No. EPA-HQ-OAR-2005-0083-0044, p. 19) We also note that the French Basic
Safety Rule III.2.f states, "The characteristics of man will be considered to be constant
(sensitivity to radiation, nature of food, contingency of life, and general knowledge without
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assuming scientific progress, particularly in the technical and medical fields)" (Docket No.
EPA-HQ-OAR-2005-0083-0389, Section 3.2). Similarly, guidance issued by the Swedish
Radiation Protection Authority (SSI FS 2005:5, "Biosphere conditions and exposure
pathways", Docket No. HQ-OAR-2005-0083-0388) states:
"Unless it is clearly unreasonable, however, today's biosphere conditions at the
repository and its surroundings should be evaluated, i.e., agricultural land, forest,
wetland (mire), lake, sea or other relevant ecosystems.. .the selection of [exposure
paths] should be based on an analysis of the diversity of human use of
environmental and natural resources which can occur in Sweden today."
Regarding the agreement of biosphere and climate, we addressed in our proposal the idea
that the RMEI characteristics could change with climate, in the sense that other lifestyles
might be expected to become more prominent in a cooler, wetter climate (70 FR 49023).
However, we continue to believe that the RMEI would represent a reasonably conservative
scenario, particularly in its use of ground water, even under changed climate conditions.
Historical evidence suggests that Yucca Mountain would not be expected to undergo
glaciation such as has occurred in Northern Europe, which would significantly affect the
biosphere and human behavior (Viability Assessment of a Repository at Yucca Mountain:
Volume 3, Total System Performance Assessment, DOE/RW-0508). (See also Sections 2
and 8 of this document.)
Comment 0226-95 criticized our inclusion of specific instructions for the treatment of some
features, events and processes (FEPs) and eliminating them from consideration in
compliance assessments as undercutting the treatment of uncertainties. We believe that the
particular details we have included in the final standards do not eliminate necessary FEPs
from consideration, but merely remove areas of unresolvable and, therefore non-productive
speculation from the safety assessments. More specifically, our stipulations on the
assessments of climate change in safety assessments do not remove the need to consider
significantly increased precipitation during long-term climate cycles over the period of
geologic stability. Rather, by allowing averaged values of precipitation (or other
appropriate climate-related parameters) estimated for such cycles to be used in the
assessments, we remove an unresolvable question about the exact timing and extent of
individual "spikes" in precipitation. The need to consider increased precipitation is not
removed from the assessments, and the effects of the increased precipitation are still fully
included in the assessments. What are removed are the purely speculative aspects of
projecting exact timing and magnitude of future climate changes. (See Section 8 of this
document for more discussion of climate change and Section 16 of this document for
discussion of FEPs.)
Comment 0226-25 suggests that EPA describe various types of uncertainty. We believe
that the discussions of uncertainty in the technical support document ("Assumptions,
Conservatisms, and Uncertainties in Yucca Mountain Performance Assessment," Docket
No. HQ-OAR-2005-0083-0085) provide a thorough discussion of the uncertainties in
assumptions built into DOE modeling approaches (such as choices in corrosion
mechanisms), and uncertainties in data used in safety assessments (corrosion rate data for
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example). Our analyses examining various types of uncertainties in disposal system
performance assessments provide detailed discussions of the uncertainties, their behavior
over time and implications for performance assessment analyses and dose projections.
(Docket Nos. EPA-HQ-OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-0429)
Comment 0263-1 stated that the spread of results in safety assessments over time is a
measure for the acceptability of the repository site. We believe that this outcome of the
assessments is the product of increasing uncertainty in the data base used in safety
assessments, and taken alone it should not be the deciding reason for rejecting the site.
While the implications of uncertainties should be understood and evaluated, we believe that
the compliance decision that NRC will make should not be based on quantitative
projections alone for such extended periods, but also with due consideration to the principle
of reasonable expectation in evaluating the overall character of those projections. The
compliance decision NRC will make will be based upon its regulations, since NRC has the
responsibility for granting the license to operate the disposal system. (See Docket No.
EPA-HQ-OAR-2005-0083-0376, p. 45 for discussion of NRC considerations in
determining "reasonable expectation.") In line with these statements, we agree with the
points raised by Comment 0186-18, i.e., that uncertainty in projecting doses with time is a
contributor to uncertainty in regulatory decision making and must be factored into the
regulatory process that NRC will execute. Our description of the "reasonable expectation"
concept (see Section 17 of this document) provides some additional insight on the role of
this concept in regulatory decisions.
Comment 0311.1-11 contends that EPA failed to explain why 10,000 years is an
appropriate time for the evaluation of uncertainties. Contrary to the commenter's
statement, we have not viewed 10,000 years as a "magic dividing line" where uncertainties
"eliminate credibility altogether." We emphasized in our proposal that uncertainties do not
become unmanageable immediately after 10,000 years, but will become progressively
greater over long time frames. However, there is a body of experience that suggests
uncertainties associated with this shorter time frame can be effectively addressed in a
regulatory setting, where no such experience exists for periods as long as 1 million years.
The 10,000-year component is directly comparable to the level of protectiveness provided
in 40 CFR part 191 and adopting it for Yucca Mountain maintains consistency with other
applications of deep geologic disposal (WIPP in particular). We believe that this
requirement forces the development of a disposal system that will provide at least as
protective a situation as would be mandated if 40 CFR part 191 were applied to Yucca
Mountain. We believe this will lead to a more robust disposal system when combined with
the peak dose standard beyond 10,000 years, which we are establishing in response to the
NAS recommendations and the D.C. Circuit ruling.(Docket No. EPA-HQ-OAR-2005-
0083-0414)
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Comment 0324-31 misinterpreted the statement in the preamble to the proposed rule. We
were discussing the uncertainty involved with determining performance of any repository
out to time frames on the order of 1 million years. The commenter is incorrect if he meant
to imply that uncertainty would vanish if a different repository site were selected. That is
not the case. Projecting disposal system performance, including the natural barrier, over
very long time periods is uncertain by its very nature for any potential situation. The
Yucca Mountain site has been selected through the process mandated by law and it is not
EPA's mandate to judge the merit of the site relative to other potential disposal sites.
Further, EPA's task, as outlined in the NWPA, was to set generally applicable
environmental radiation protection standards. Our task under the EnPA is to set site-
specific public health protection standards for Yucca Mountain. We believe that we have
done so. It is NRC's responsibility to implement our standards by revising its licensing
requirements to be consistent with our standards and using them in the decision on the
acceptability of the Yucca Mountain disposal system. The DOE is responsible for siting,
building, and operating an underground geologic disposal system for SNF and HLW. It is
also DOE's responsibility to show that a proposed disposal system will meet the standards
put in place by EPA and implemented by NRC. It is NRC's responsibility to evaluate
uncertainties involved in DOE's site description and dose assessments in its decision
making (Comment 0186-18). The process executed to select the Yucca Mountain site from
among other alternatives also examined the relative uncertainties of the individual sites and
reached the conclusion that the site was sufficiently understandable to proceed with site
characterization.
One comment (comment 0314.1-8) suggests we should adopt the French approach to dose
assessments, i.e., the use of "scientifically reasonable, but highly conservative choices for
important parameter values." We find this description contradictory in that it is difficult to
call a parameter value selection scientifically reasonable, implying a realistic approach to
parameter value assignment, while also being highly conservative, which implies a
departure from any attempt to perform realistic modeling. We believe it is DOE's
responsibility to determine the approach used for disposal system performance assessments
for licensing (e.g., to decide upon the degree of conservatism in their dose projections), and
NRC's responsibility to evaluate their choices in the context of the licensing process.
Therefore we do not believe it appropriate to mandate any particular approach to selecting
parameter distributions for DOE's performance assessments. More discussion of the
French and other international approaches may be found in Section 4 of this document.
We do not believe the analogy Comment 0226-30 draws between the treatment of
uncertainties for the Yucca Mountain situation and the treatment of uncertainty in
regulatory activities aimed at managing fish populations is appropriate. The wildlife
management situation deals with an active system that can be monitored and modified over
the regulatory time frame, whereas the potential Yucca Mountain disposal system is a
passive system that requires a realistic recognition of the nature of the system's
uncertainties and the limits they impose on performance projections over the compliance
period.
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Section 6 Uncertainty
Issue D: Cohen uncertainty report
1.	EPA assumes that DOE's models will be overly negative in their predictions of
repository performance, and that EPA must therefore create a lax rule to accommodate or
balance out that negativity. The first major problem with EPA's over-conservatism
rationale is that EPA never explains it. EPA never describes the logical link between an
overly conservative analysis and a more lax, second-tier standard. Nevada infers that EPA
believes the standard must be lax to accommodate perceived weaknesses in the modeling,
but EPA itself has never specified this or any other rationale. But even this rationale, if
expressed, would be unreasonable, for the proper remedy for flawed modeling is to fix the
modeling, not to weaken the standard. If EPA intended to say that, because of inevitable
increased conservatisms after 10,000 years, a 350 millirem/year standard is the equivalent
of 15 millirem/year, it has failed to support its premise. In fact, the opposite premise is the
more supportable one. (Comment 0226-39)
2.	EPA cites a 2005 report prepared by its contractor, Cohen and Associates. But that report
cannot support any proposition about the degree of conservatism in DOE's analysis. To
evaluate whether DOE's past modeling was overly conservative, the report would have
needed to determine which assumptions were conservative and which were optimistic. It
would then have needed to quantitatively assess the relative importance of those
assumptions to determine whether the overall results were shifted toward conservatism or
optimism. Because some degree of conservatism normally is considered desirable in a risk
projection—particularly where, as EPA repeatedly states is the case, there is some
uncertainty about the projections—EPA would also need to determine whether any
resultant shifting of the projections was excessive. (Comment 0226-40)
3.	The Cohen report contains no such analysis. Instead, it provides a qualitative and almost
totally one-sided discussion. It summarizes almost every assumption that could conceivably
be characterized as conservative, sometimes even double-counting the same assumptions.
With the exception of a handful of pages in chapter 5, however, the report does not even
consider whether optimistic assumptions have been made. Also, nowhere does the report
perform any quantitative analysis of the effects of the assumptions it identifies, let alone
quantitatively address the effects of the optimistic assumptions it ignores. The report is like
a legal analysis that addresses only one side of an argument; it is completely unbalanced
and provides no basis for EPA to conclude that DOE's modeling is overly conservative.
Moreover, the Cohen report fails to support the actual rule proposed by EPA which
eliminates many uncertainties and potential conservatisms from the analysis. (Comment
0226-41)
4.	EPA's conservatism rationale also fails to explain why conservatism is inappropriate. To
the extent conservatisms are unnecessary, and can be replaced by more realistic analyses,
this is the appropriate solution - not weakening the standard. By premising the rule on
alleged conservatisms after 10,000 years, the rule has the effect of discouraging DOE and
NRC from doing more realistic analyses, lest the premise for application of EPA's rule is
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found lacking and the licensing process be thrown into confusion. To the extent the state of
scientific knowledge does not permit realistic analyses, then bounding assumptions and
analyses are inevitable, but we have no way of knowing how such bounding assumptions
and analyses are conservative. It defies scientific logic to give credit for "conservatisms"
when it cannot be established whether the conservatisms actually exist. EPA traditionally
considers conservatism an important and necessary response to this kind of uncertainty.
Such conservatism is particularly important for Yucca Mountain, because EPA's standard
and NRC's licensing process will likely be the only opportunities to "test" the safety of the
repository design. If DOE, EPA, and NRC eschew conservatism in their approval process
and allow the construction of a repository with only a moderate probability of success, they
will create a major risk for future generations—without giving those future generations any
tools to manage that risk. Those future generations may not have any ability to undo
repository failures, or even to know that the repository exists. A conservative standard now
will be the primary protector of their safety. (Comment 0226-42)
5.	The greatest uncertainty in the performance of the repository relates to the timing of the
peak dose, which is itself entirely dependent on the lifetime of man-made waste packages.
If DOE's optimistic assumptions about container life are wrong, then DOE's entire
performance evaluation becomes extremely non-conservative. EPA itself has noted the
importance of this issue, which, if DOE's assumption is wrong, has led modelers to vastly
overestimate the ability of the repository to contain waste. (Comment 0226-43)
6.	There is no disagreement that DOE's waste containers eventually will inevitably fail, and
that Yucca's geology will permit leaking radionuclides to reach the accessible environment.
The timing of that failure is uncertain, for DOE is proposing to employ engineered systems
that have never been tested on anything approaching the time scales over which DOE
hopes they will provide protection. (Comment 0226-44)
7.	Finally, there is no genuine dispute that the resistance—or lack thereof—of the
containers to corrosion is the crucially important determinant of the timing of peak dose.
In its recent report, EPA's contractor provided a detailed discussion of DOE's lack of
knowledge about when its containers will fail. Initially, the Cohen report noted that DOE's
proposed system is unique. "Unlike most concepts adopted by other nations," it stated, "the
proposed Yucca Mountain repository exposes the metallic waste packages and drip shields
to sustained oxidizing conditions." Cohen at 5-1. It then noted that the performance of that
unique system was difficult to predict. "Engineering experience," the report stated, "with
passive metals is extremely short (i.e., approximately 100-150 years) compared with the
timeframe of repository performance projections. Extrapolation of present knowledge to
the longer timeframe is thus highly uncertain." Id. at 5-13 (parentheses in original). It later
added that "[t]he failure, to date, to identify clear natural or archeological analogs for long-
term passive metallic behavior seriously limits confidence regarding the stability of passive
films in providing extremely long-term corrosion resistance." Id. at 5-15. (Comment 0226-
45)
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8.	In drawing these conclusions, the Cohen report cited, and followed, the conclusions of
leading corrosion experts. In 2001, an expert panel considered corrosion risks to the Yucca
Mountain containers. That panel "called attention to how little is presently known about the
nature of passive film on Alloy 22," and it considered a series of ways in which the
containers might fail. See id. at 5-15 to 5-16 (quoting Sagues, 2002). The Cohen report
also emphasized the threat of unanticipated modes of corrosion. "[UJnexpected modes of
alloy deterioration often emerge when service conditions deviate (even on a microscopic
scale) from anticipated regimes," it wrote, and it concluded that "the possibility of other
unexpected but potentially severe deterioration mechanisms developing into the far future
cannot be dismissed easily." Id. at 5-13 (parentheses in original). The expert review on
which the Cohen report relied similarly identified a series of potential failure modes that
would merit further study. In addition to being highly uncertain, the corrosion resistance of
the casks is critically important. The Cohen report notes that "the choice of corrosion rates
for the performance projections is a major factor in both estimating the magnitude and time
of peak dose projections." Cohen at A-20. EPA similarly emphasizes that corrosion is
"exactly the critical element in estimating timing and magnitude of peak dose." 70 FR
49026. This importance exists for an obvious reason; because water always is percolating
through Yucca Mountain, radionuclide transport will begin as soon as radionuclides are
released, and corrosion rates therefore will determine when releases take place. The effect
of those corrosion rates on repository performance is so great that EPA's own economic
impact analysis suggests that there is little value in attempting to reduce any other sources
of uncertainty. Cohen at A-20. EPA's own documents indicate (1) that the rate of corrosion
is of enormous importance; and (2) that EPA and DOE have very little certainty about how
quickly corrosion will occur. Nevertheless, DOE's models, to date, consistently have
assumed that no corrosion-related failure will occur during the first 10,000 years of the
repository lifetime, and, indeed, that robust corrosion resistance will continue for additional
thousands of years. DOE thus has assumed the certain performance of one of the most
uncertain aspects of the repository system. This assumption undermines EPA's theory that
DOE's modeling will be "overly conservative." DOE has made highly optimistic
assumptions about the single most critical variable affecting repository performance,
notwithstanding the "various sources of worse-than-anticipated performance of the WP that
have not been sufficiently investigated, or, in some instances, would be very difficult to
evaluate in a short research period." Cohen at 5-16. That assumption leaves DOE's analysis
as optimistic as a safety assessment of the Titanic that assumed the ship certainly would not
collide with icebergs, or an analysis of the Hindenburg's safety that ignored the potential
proximity of sparks. (Comment 0226-46)
9.	Corrosion assumptions are just one of many potential sources of optimism in DOE's
proposed modeling. Neither DOE nor EPA has done a comprehensive analysis of
optimistic assumptions and their potential consequences, but several other assumptions and
modeling techniques could similarly skew the analysis. For example, EPA's proposed
exclusions of criticality events, EPA's ratification of DOE's assumption of the nonexistence
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of manufacturing defects, EPA's exclusion of natural events it considers "unlikely," and
EPA's exclusion of localized corrosion and other potential engineering problems all would
skew DOE's modeling toward potentially excessive optimism. See discussion infra on
FEPs. That excessive optimism vitiates any attempt by EPA to rely on supposed "over-
conservatism" as a justification for a lax second-tier standard. (Comment 0226-47)
Response to Issue D:
The purpose of the technical support document referred to by the commenter
("Assumptions, Conservatisms, and Uncertainties in Yucca Mountain Performance
Assessments," prepared under contract to EPA by Sanford Cohen & Associates, Docket
No. EPA-HQ-OAR-2005-0083-0085) was to provide a framework for understanding the
safety analyses that have been performed for the Yucca Mountain site, and provide some
insight necessary for the Agency to evaluate the effects of uncertainty in the far future.
Most of the comments make reference to the connection between uncertainty and
performance projections for the site particularly in connection with the longevity of the
metal containers (Comments 0226-43, 0226-44, 0226-45, 0226-46, and 0226-47),
conservatism in the DOE performance assessments (Comments 0226-40, 0226-41, and
0226-42), and the connection between uncertainty in general and the two-tier standard
(Comments 0226-39 and 0226-47). These comments were made in the context of the
proposed peak dose limit of 350 mrem/yr. and imply a connection between that limit and
our examination of assumptions and conservatism in past DOE performance assessments of
the Yucca Mountain site. We have not adopted the 350 mrem/yr peak dose in the final
rule. In proposing the 350 mrem/yr limit, as well as setting the 100 mrem/yr peak dose
limit in the final rule, the assumptions, either conservative or optimistic, in DOE's
assessments were not the basis for the decisions. The intent of our examination of the
assumptions and conservatisms in DOE performance assessments was to understand the
processes operative in the disposal system and their interplay in long-term dose projections
and we believe the report provided this insight. The comments received concerning
specific aspects of these processes and performance analyses are welcomed and add to the
insights provided in the report.
On the general topic of conservatism, Commenter 226 states that we have overcompensated
for perceived conservatisms in DOE's modeling, while at the same time given too much
credence to DOE's non-conservative assumptions regarding waste package performance.
The commenter concludes that we have "premis[ed] the rule on alleged conservatisms after
10,000 years," which "has the effect of discouraging.. .more realistic analyses" (Comment
0226-42). The commenter states that the legitimate way to address excessive conservatism
in modeling is to "fix the model," rather than change the standard. Here again, we did not
base standard on the information in the critiqued report.
We do not believe we have prejudged the amount of conservatism in DOE's modeling, nor
have we concluded that conservatism is inappropriate or that the total system assessments
are overly conservative. Our assessments of the assumptions and conservatisms in the
DOE assessments were performed to provide us with some insight into the behavior of the
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disposal system under various conditions and performance scenarios. The degree of
conservatism and its relation to uncertainties in projecting long-term performance are a
major part of the NRC's task in evaluating the site's projected performance and making a
compliance decision relative to our standards. To construct a standard that is a reasonable
test of the disposal system performance we need to understand how the disposal system is
anticipated to perform. The referenced report was intended to provide such insights. We
recognize that introducing conservatism is a common, and generally accepted, way to help
address the effects of uncertainty. In our proposal, we stated that "conservatism in long-
term performance projections may be unavoidable in practice" (70 FR 49042) but "realistic
analyses are preferred over conservative and bounding assumptions, to the extent practical"
(70 FR 49021). We note that some comments disagreed with this position, suggesting that
increased conservatism is warranted for assessments covering longer time periods (see
Issue C in this section).
We did caution strongly against the use of excessive conservatism in either the models or
in developing the parameter value distributions, and do not agree with the implication of
many commenters that a more conservative approach is preferable to more realistic
analyses whenever possible. Excessively conservative assumptions for various aspects of
the modeling are not desirable and can lead to assessments based on a system that is
unlikely to exist. The decisions that follow from such assessments would then be focused
on extreme situations. We recognize that it may be very difficult to identify and
characterize conservatisms over very long time periods, as the characteristics of the
disposal system evolve over the long-term in ways that are not completely predictable.
However, we believe DOE's assessments should reflect the best understanding of the site
and the evolution of the disposal system over time. Transparency in identifying such
conservatisms as are deemed necessary and appropriate in assumptions and parameter
values, and the uncertainties associated with them, will aid NRC in determining with
"reasonable expectation" that the dose assessments will or will not comply with the
standard. NAS expressed a similar view in stating that "transparency in the use of
assumptions is critical to evaluating the calculated risk." (NAS Report p. 69) Similarly, we
noted in our proposal that the IAEA-NEA Peer Review of DOE's TSPA-SR model
recommended that DOE present "analysis based on a realistic or credible representation" as
well as "complementary analyses with different conservatisms, in order to place the best
available knowledge in perspective" (70 FR 49028). As an example of the need for
transparency of assumptions, an independent evaluation of DOE's assumptions for igneous
scenarios concluded that those assumptions led to calculated doses that were nine orders of
magnitude higher than "realistic" assumptions ("Evaluation of the Igneous Extrusive
Scenario," Presentation to the Nuclear Waste Technical Review Board, September 20,
2004, Docket No. EPA-HQ-OAR-2005-0083-0074). In many cases, there may be no clear
line between "conservative," "realistic," and "optimistic" assumptions. In some cases,
assumptions or parameter values may be labeled as conservative when there is insufficient
evidence to support that claim, meaning they may actually be seen as realistic if more
information were available. We believe it is the consistent reliance on conservatism when
choices present themselves that should be viewed with caution. Application of the
principles of "reasonable expectation" should ensure that the analyses do not rely on
extreme assumptions or parameter values, whether conservative or optimistic. Instead, the
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full range of reasonable and defensible parameter values will be emphasized in the
performance assessments and considered in reaching a compliance determination.
The commenter also cites, we believe incorrectly, several "optimistic" assumptions that our
proposal would allow (Comment 0226-47). With the exception of a criticality event, which
we concluded would not be significant at very long times (Docket No. EPA-HQ-OAR-
2005-0083-0082), the examples cited by the commenter are related to the probability
screening threshold established for inclusion of features, events, and processes (FEPs) in
the analyses. Without dwelling on the interpretation of "unlikely" vs "very unlikely" FEPs,
our individual-protection standard allows FEPs to be categorically excluded only if they
have an annual probability of occurrence less than 1 in 100 million (10"8). This equates to a
0.01% chance of occurrence over 10,000 years, and only 1% chance of occurrence over 1
million years. We view this as casting a very wide net for potential FEPs, and hardly one
that would lead to "optimistic" assumptions. In fact, FEP screening is not connected to the
nature of assumptions used in modeling disposal system performance for the FEPs included
in the modeling. The choice of optimistic or pessimistic assumptions about the processes
included in the site conceptual model are determined by the analysts (using the information
gathered during site characterization and from laboratory testing) after the FEPs have been
screened for inclusion or exclusion on the basis of probability. "Unlikely" FEPs, as
defined by NRC, may be excluded from the human-intrusion and ground-water protection
analyses (40 CFRPart 197.36(b)). Further, this probability threshold also applies to FEPs
affecting the engineered barriers, including "manufacturing defects" and "localized
corrosion and other potential engineering problems" (as well as criticality events). Thus,
we have neither "ratified DOE's assumptions" nor "excluded" these potential FEPs.
Localized corrosion is recognized as a process that could be initiated relatively early in the
disposal period, when temperatures are high. Our standards require that FEPs operating for
the initial 10,000-year period continue operating throughout the period of geologic
stability, so that FEPs that are influential at early times are in no way excluded from the
longer-term analyses. Localized corrosion differs from general corrosion in its early
significance for waste package failure, whereas general corrosion operates over a much
longer time period and eventually causes waste package failures at longer times, which is
why we explicitly included general corrosion in our proposal. As with all FEPs, DOE will
have to defend its assumptions regarding waste package failure mechanisms. More
detailed discussion of FEPs may be found in Section 16 of this document.
As the comments point out correctly (Comments 0226-43, 0226-44, 0226-45, 0226-46, and
0226-47), corrosion of the metal barriers (the waste containers and the surrounding drip
shields) is a critical process in determining the range of potential releases from the
repository, both within the 10,000-year period and through the remainder of the period of
geologic stability, and is a significant issue for long-term performance (Comments 0226-
40, 0226-41, and 0226-42). We agree with the commenter's observation about the
importance of corrosion rate assumptions and dose projections. This observation is also
confirmed by our modeling examining the interplay of major "driver" parameters
controlling the timing and magnitude of the peak dose (Docket Nos. EPA-HQ-OAR-2005-
0083-0414 and EPA-HQ-OAR-2005-0083-0429). Variations in assumed corrosion rates
caused the peak dose to move beyond the stability period for some assumptions or move
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forward in time and increase significantly in size relative to a defined reference case.
Variations in the amount of ground water entering the emplacement drifts can also act to
counterbalance the effects of increased waste package failure rates or increase doses
dramatically for given corrosion rate assumptions.
As noted above, NRC will evaluate DOE's assumptions regarding engineered barrier
performance. Alternative assumptions may result in projections of significant early
releases, as well as potentially dramatic changes in the timing and magnitude of the peak
dose. To gain insight into the interplay of process in the natural and engineered barriers
over the compliance period, we performed some modeling to examine the contributions of
various processes, and the contributions of various types of uncertainty, to peak dose
projections. (Docket Nos. EPA-HQ-OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-
0429) Using a less elaborate site model than that used for DOE's total system analyses
(TSPA), we gained some insight into the possible behaviors of the disposal system. The
potential corrosion resistance of the metal barriers alone, or uncertainty in any other
components of the disposal system, is not a basis for setting any particular peak dose limit,
as the comments correctly point out. However, it does provide insight into the
implementability of the standards and how to construct a reasonable test of the disposal
system performance which was not the purpose of the Cohen report, but the peak dose limit
was not determined using that document (Comments 0226-39 and 0226-47).
EPA has performed some analyses to determine the implications of extending the
regulatory time period past 10,000 years, the limit in previous applications for deep
geologic disposal, and out to time frames as long as 1 million years ("Modeling
Uncertainty Effects on a Reference Dose Level," December 2006, Docket No. EPA-HQ-
OAR-2005-0083-0386). These analyses look specifically at the range of uncertainty in
projecting the peak dose if the Yucca Mountain disposal system were to be at the "edge of
compliance" at 10,000 years, i.e., if, hypothetically, a sufficient number of waste packages
had failed and were releasing radionuclides into the natural barrier such that the RMEI
would experience a dose of 15 mrem/yr at year 10,000. The Agency performed modeling
using a site-specific model (although less detailed than the TSPA models used in
previously published DOE assessments), which was modified to address the corrosion issue
by removing the drip shield totally from the analyses and deliberately failing waste
packages until a 15 mrem/yr dose was produced at 10,000 years. By eliminating the
containment capability of the engineered barrier system and thereby fixing the source term
for releases into the natural barrier, a major component of uncertainty was removed from
the hypothetical disposal system, essentially removing the "optimistic" perspective on
corrosion rates mentioned in some comments from the analyses (Comment 0226-47). This
system, with the fixed number of failed waste packages, was then modeled to explore the
range of potential doses for the range of potential values for important site parameters (and
their uncertainty) that determine dose levels. This analysis indicated that the hypothetical
system at the "edge of compliance" at 10,000 years (showing a mean dose of 15 mrem/yr),
the existing limit for an acceptable disposal system at 10,000 years, would produce a range
of exposure values at peak dose over a million years of several hundred mrem/yr, for
various choices of modeling options. The variation in dose levels at 10,000 years for the
hypothetical system (the difference in dose levels between to 5 and 95 percentile of the
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dose distributions at 10,000 years and at peak dose) increased approximately two orders of
magnitude from the starting point at 10,000 years, reflecting an increase in uncertainty over
that time period due to variations in the natural barrier site conditions. (Docket No. EPA-
HQ-OAR-2005-0083-0386) This technical analysis supports our belief that long-term
projections should be viewed as qualitatively different from shorter-term projections in the
context of decision-making. Extensive descriptions of these analyses are presented in the
referenced reports in the docket.
We disagree with the comment that the peak-dose standard is a "relaxed" standard
(Comment 0226-47). The modeling described briefly above sheds some insight into this
question. Results of our modeling to examine "driver" parameters controlling the peak
dose (Docket Nos. EPA-HQ-OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-0429)
show that a hypothetical disposal system giving a 15 mrem/yr mean dose at 10,000 years
would produce peak doses in the range of several hundred mrem/yr under the site
conditions at Yucca Mountain for a scenario where the number of waste package failures
was kept at a fixed level. Other simplified modeling we performed (Docket Nos. EPA-HQ-
OAR-2005-0083-0414 and EPA-HQ-OAR-2005-0083-0429) leads to the conclusion that a
peak dose limit in the low hundreds of mrem/yr constrains the disposal system to keep
releases well below 15 mrem/yr for periods well in excess of 10,000 years in order to meet
a 100 mrem/yr peak dose limit. We have set the peak dose limit at 100 mrem/yr for
reasons not based on our modeling results, but these results and the insights they provide to
the Yucca Mountain disposal system behavior, indicate that the 100 mrem/yr limit appears
to impose significant constraints on the disposal system to minimize releases for periods of
many tens to hundreds of thousands of years after repository closure. Therefore the
addition of a peak dose standard at 100 mrem/yr provides more protectiveness than a
10,000-year standard alone. We do not agree that the standard is weakened by the addition
of a peak dose limit of 100 mrem/yr. (Comment 0226-31) We believe that the peak dose
limit we have established is an appropriate and protective health protection standard for
periods approaching 1 million years, and that it provides a reasonable test of the disposal
system consistent with the NAS recommendations, D.C. Circuit decision, and principles of
reasonable expectation.
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Section 7 Use The Mean Or Median?
Issue A: Prefers the mean or median
1.	This proposal is in contrast to use of the mean (i.e., arithmetic mean) of a probability
distribution of projected doses at times up to 10,000 years. Of all the statistical measures
... that EPA might have chosen for comparison with a dose criterion, I believe that the
median clearly is the least appropriate. The fundamental problem with using the median
..., rather than the mean or some other percentile above the median, is that the median is
insensitive to uncertainties in projected doses. In representing a probability distribution by
a single number (measure) that is to be compared with a specified dose criterion, it is
essential that the chosen measure of a probability distribution of projected doses be
sensitive to uncertainties. Furthermore, the measure of a probability distribution of
projected doses to be used in compliance demonstrations must increase as uncertainties
increase. The mean of a probability distribution has this essential property when the mean
exceeds the median, which will always be the case in performance assessments at Yucca
Mountain, but the median does not. It is important to note that projected doses will not
resemble normal distributions, for which the mean and median are the same. ... EPA has
argued that the arithmetic mean should not be used because the mean is too greatly
influenced by extremes in a probability distribution. EPA's arguments are weak and, it
seems to me, without merit. It is precisely because the mean is sensitive to upper tails of
probability distributions of projected doses at Yucca Mountain, which clearly are of
greatest interest in evaluating overall safety of the facility, that the mean is a valid and
useful measure of a probability distribution in judging compliance with dose criteria.
(Comment 0186-9)
2.	There are two reasons why use of the mean does not unreasonably distort probability
distributions of projected doses. First, as EPA's discussion makes clear, projected doses
toward the upper end of probability distributions are weighted by their probability of
occurrence, and those probabilities generally will be low. Second, related to the concept of
"reasonable expectation" is the important point that NRC should have the authority to judge
whether the highest projected doses that influence the mean of a probability distribution are
reasonable, i.e., whether they represent reasonable outcomes. It is not,
(and it should not be), EPA's responsibility to try to eliminate by regulation possible
difficulties in compliance demonstrations that might result from a few unusually high
projections of dose. (Comment 0186-10)
3.1 have two further arguments against EPA's proposed use of the median. First, when the
median of a probability distribution of projected doses is used at times beyond 10,000 years
but the mean is used at earlier times, the difference between the dose criteria in the two
time frames is not presented realistically. In reading the regulations and Supplementary
Information, it would be easy to conclude that the proposed dose criterion at times beyond
10,000 years is a factor of 3.5/0.15 = 23 less restrictive than the dose criterion at earlier
times. However, when probability distributions of projected doses are taken into account,
the degree of relaxation in the dose criterion beyond 10,000 years probably will be much
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greater. Suppose, for example, that at times beyond 10,000 years when projected doses are
the highest, the 90% credibility interval spans three orders of magnitude (i.e., the 95th
percentile of the probability distribution is a factor of 1,000 higher than the 5th percentile);
DOE calculations I've seen indicate that this probably is a low estimate of uncertainty. If
probability distributions of projected doses are approximately lognormal, which should be
the case, the mean would be about 9 times higher than the median, and the degree of
relaxation of the standard would be about a factor of 23 x 9, or about 200. The actual
uncertainty could be well in excess of three orders of magnitude, in which case the degree
of relaxation of the standard would increase greatly. If the uncertainty is four orders of
magnitude, for example, the mean would exceed the median by a factor of about 50, and
the degree of relaxation of the standard would be a factor of about 23 x 50, or more than a
factor of 1,000. If EPA believes that an annual dose of 0.15 mSv represents an upper bound
of an acceptable dose at times up to 10,000 years, it is very difficult to justify that annual
doses in the range of about 30-200 mSv would be acceptable at times beyond 10,000 years.
Thus, a major shortcoming of EPA's argument in favor of using the median dose at times
beyond 10,000 years is that EPA has not acknowledged the large relaxation in the degree of
protectiveness in their standards that the change from a mean to a median probably
involves. (Comment 0186-11)
4.	My second argument against use of the median is similar to EPA's argument against use
of the geometric mean, which is that projected doses of zero, or close to zero, would
determine the geometric mean. Suppose, for example, that 51% of all calculated doses in a
probability distribution are either zero or very small, as in EPA's discussions of very small
but meaningless doses. In this case, use of the median would lead to the absurd result that
the "best estimate" of the dose is zero, even though almost half of the doses are greater than
zero and, indeed, could be quite large. Does EPA seriously believe that this is a reasonable
interpretation of the calculated probability distribution in this case? This example clearly
illustrates why the median is a very poor representation of a probability distribution for
purposes of compliance demonstrations. (Comment 0186-12)
5.	The standard is an average dose rather than a maximum permitted dose. Large numbers
of people will get doses far higher than this average dose with proportionally higher risks.
Half the radiation scenarios will result in doses higher than that. There is no upper limit for
the half of the exposures that would be above the median. Let's be clear about this. There
is no upper limit to the dose at all. Dozens of the 300 or so exposure scenarios that DOE
would run would result in doses above the 350 millirem or 1,000 millirem doses. In other
words, under the EPA standard, significant numbers of people would be exposed to doses
that would produce a statistical 100 percent chance of inducing cancer in exposed people.
A hundred percent risk of cancer is unacceptable. (Comment 0209.12-6)
6.	[Use of the median] is a highly significant shift; DOE's current modeling predicts that at
peak dose, mean values will be approximately three times higher than median values, and a
350-millirem median standard is thus the equivalent of an approximately 1000-millirem
mean standard. (Comment 0226-11)
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7.	Because EPA proposes to continue using the mean, which it accurately describes as a
"familiar and well-understood statistical concept," for its 15 millirem pre-10,000 year
period, see 70 Fed. Reg. at 49042, its post 10,000-year standard will be almost seventy
times higher than its pre-10,000 year standard. This shift may be (and appears calculated to
be) outcome-determinative; DOE's TSPA modeling suggests that Yucca could just barely
meet a median-based standard, but would grossly fail a standard based on the mean.
(Comment 0226-12)
8.	EPA's shift from the mean to the median also marks a dramatic departure from EPA's
prior approach. In its prior rulemaking, EPA initially proposed to use the higher of the
mean or median, and eventually settled on the mean as its chosen compliance measure. In
the 1999 proposed rule for Part 197, EPA stated that: "As a result of the performance
assessment there will be a distribution of the highest potential doses incurred by the RMEI
[Reasonably Maximally Exposed Individual], We are proposing that the mean or median
value (whichever is higher) of that distribution be used by NRC to determine compliance
with the individual protection standard." 64 Fed. Reg. 46988. In the June 2001 Final Rule,
EPA [confirmed use of the mean], 66 Fed. Reg. 32125 (emphasis added). EPA went on to
consider many of the rationales it now offers for selecting the median, but it rejected them,
concluding instead "that, in the case of Yucca Mountain, the mean is an appropriate
measure." Id. In its June 2001 Responses to Comments in its prior rulemaking on Part 197,
EPA similarly made clear that it would employ the mean rather than the median (pp. 4-7, 7-
3, 7-4, 7-5, and 7-6). (Comment 0226-13)
9.	[BJecause no model run outcome is assumed to be more likely than any other modeling
run, the mean, which treats each run as equally important, is more appropriate than the
median, which treats higher, more dangerous outcomes as less important outliers. In
contrast, the median artificially discounts high dose realizations (the distributions tend to be
positively skewed) simply because they are high, with no justification in sound science, and
notwithstanding that the doses are already weighted by their associated probabilities. Put
another way, use of the mean violates the principle that all realizations are presumed to be
of equal weight, absent some actual investigation of particular outliers that would raise
questions about their scientific validity... EPA's selection of the median is based on a
basic misunderstanding of statistics. EPA repeatedly states that the median avoids placing
"undue" emphasis on extreme events. [A] statistical measure specifically designed to throw
out the higher numbers introduces a pronounced, non-conservative, and irrational skewing
effect. But the mean is not skewed, as EPA implies, by those higher outcomes; in the
averaging process, the results are treated as equally likely and important. No other
approach is rational. (Comment 0226-14)
10.	The selection of the median is statistically inappropriate for another reason. By
selecting the median, which considers only the number, but not the magnitude, of "bad"
(i.e. above-the-median) outcomes, EPA has declined to consider the degree of harm
threatened by each of those bad events. Use of the median will discourage any investigation
of high dose calculations since those high doses will have little or no effect on compliance.
Indeed, use of the median will permit a finding of compliance notwithstanding hundreds of
dose calculations showing lethal doses of radiation, because the median is insensitive to the
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actual magnitude of the approximately 42% of the dose calculations above it. As a
hypothetical example, if 149 realizations (calculations) showed Yucca Mountain would
destroy all of the nearby Nevada residents, but 151 of the realizations showed a dose of less
than 350 mrem, the EPA approach would pass the repository. The reality is that for any
safety evaluation, the magnitude of any potential bad outcomes does matter, and the mean
takes that magnitude into account whereas the median does not. In fact, as Dr. Thorne
points out (see Appendix C), the median has no well defined relationship to health
detriment, so that EPA's proposed use of the median effectively severs the dose standard
from the actual harm it is supposed to prevent. Such a standard is not even health-based, as
required by law. (Comment 0226-16)
11.	EPA fails to explain why focusing on "bad" outcomes is inappropriate for a safety
analysis. Indeed, the typical goal of nuclear safety analysis is to focus precisely on the
potential bad outcomes. The core purpose of a health and safety analysis is to figure out
what will happen if things go wrong. No one would ever criticize levee builders for
focusing on performance during extreme weather events rather than on routine sunny days.
(Comment 0226-17)
12.	Finally, by discounting the effects of high dose calculations, use of the median also
reduces the very uncertainty EPA relies on for its choice of 350 millirem. (Comment 0226-
18)
13.	At times after 10,000 years, EPA is proposing to raise the radiological exposure
standard of 15 millirem to 350 millirem, i.e., an increase in acceptable dose by a factor of
about 23. In conjunction with this increase, the metric to determine compliance will be
changed from the mean value of dose of a number of realizations to the median dose value
of those realizations. For typical assessments of the repository at Yucca Mountain the
median value of dose is between one and two orders of magnitude higher than the mean
value of dose. Taking this difference between mean and median to be one and a half orders
of magnitude (i.e., a factor of about 32 which is the geometric midpoint of the two limits)
implies that the proposed late time radiological dose standard is about 740 times higher
than the initial 10,000 year standard when compared on a consistent statistical basis. This
proposed massive relaxation of radiological standards at 10,000 years by the EPA
illustrates their lack of regard for future generations as demanded by the NWPA.
(Comment 0263-6)
14.	For a statistical distribution, the mean provides an unbiased estimate of the expected
value. This fact is used in the field of probabilistic risk assessment to provide the estimate
of the expected value of the outcome of a model with one or more uncertain inputs. The
model results are used to make decisions regarding the expected outcome and the range of
outcomes. The assessment of the performance of the repository is no different. The mean of
the set of realizations should be used at all time to gauge compliance with regulatory limits.
The median value, while being some measure of location, does not provide an estimate of
expected outcome. In fact for repository performance the median of a set of realizations is
lower than (or much lower than) the mean or expected value. (Comment 0263-9)
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15.	The EPA erroneously attempts to statistically justify the use of the median of a set of
realizations rather than the mean for compliance because of the possibility that a few
probabilistic results (i.e., of low probability as each realization is attributed an equal
probability of occurring) may be large and thereby "distort" the mean or expected value. If
the model is correctly set up and validated these high results are meaningful and their
numerical magnitude cannot be discarded as occurs by using the median. (As an historical
aside, would the mean or median have been the best measure of evaluating probabilistic
risk in the following engineering ventures, (i) the Titanic, (ii) the Hindenburg, and (iii) the
Tacoma Bridge? In all cases these ventures were considered extremely sound at the 50%
confidence level, i.e., from the use of the median of predicted outcomes. Please do not put
EPA in the position of being responsible for a future addition to the list.) In fact the whole
probabilistic risk community understands the occurrence of the occasional high values and
for this reason always considers (as is done in the present 10CFR63) "reasonable
expectation." As discussed in item 8 [See Comment 0263-10 in Issue C of this section], the
IPR expressed concern of the diametrically opposite effect of artificially reducing (by
dilution) the mean prediction in an attempt to ensure conservative input parameters (the
IRT used the expression that increased ignorance of the system results in an improved
prediction of performance). When expected performance is dictated by a few high
consequence outcomes (as with a reactor PRA) the median provides a totally false sense of
security and safety over the use of the expected value (i.e., the mean value). The EPA
should reevaluate its position in an unbiased manner on the measure to be used to
determine compliance. (Comment 0263-11)
16.	The EPA must refrain from using the median value of a set of probabilistic realizations
and use the more statistically meaningful mean (i.e., expected) value. In addition the EPA
must establish a sensible criterion for proposed standard for mean dose value that is based
on current protective health and safety rationales. (Comment 0263-20)
17.	Another significant and inconsistent change proposed for 40 CFR 197 is how calculated
doses are compared to the standard... The inconsistency is not well explained... The
reasoning here does not mesh. Why not use the same method for all times? It appears as
though your agency is trying to be consistent with the National Academy of Sciences
recommendation on one hand, which clearly states; "We recommend that the mean values
of calculations be the basis for comparison with our recommended standards."(1995 NAS
Report p. 123), and on the hand satisfy the "needs" of the DOE to allow higher doses for
compliance after 10,000 years. By using the median, the bar of what DOE must
demonstrate is lower; by as much as 300 mrem/yr from the 2001 calculations. What is the
EPA up to? (Comment 0268-3)
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18.	EPA has exhausted its bag of tricks to justify this outlandish standard by employing
twisted logic to convince us that the better way to determine compliance with the standard
is through use of the median rather than the mean. In fact, the public - those whose health
EPA is supposed to protect - generally believes that a dose limit is what the dictionary says
it is: "An amount or quantity established as the greatest permissible." The public would
most likely not approve of using the mean either, but to use an even less protective method
of calculation is careless and an affront to those whom the Agency is supposed to serve.
(Comment 0294-3)
19.	The 1 in 36 risk figure may significantly understate true risks. EPA, in addition to
proposing a new standard 23 times more lax than the previous 15 millirem standard, has
proposed changing the way the dose is calculated. The prior rule relied upon the mean; the
new rule proposes switching that to the median. Based on prior computer runs by DOE, this
would further relax radiation standards significantly, by something on the order of three-
fold. Thus, what EPA is proposing is not really 350 millirem/year, a 23-fold increase over
the previous standard, but on the order of 1 rem per year, a 75-fold increase, which carries
with it a risk of about 1 in 10. But because the proposed standard is a median, that results in
permitting half of the exposure scenarios to yield doses in excess of the median, with no
upper limit. So, true peak doses to the public could be far, far higher than 350
millirem/year. (Comment 0296-3)
20.	We endorse EPA's decision to specify the use of median dose as the compliance
measure beyond 10,000 years. Whether to use the median of the output distribution, or any
other measure, is clearly a regulatory prerogative that is within EPA's discretion. There is
no standard statistical approach stating whether the mean (whether arithmetic or geometric)
or the median is a more appropriate measure of the central tendency of the distribution. We
agree, as EPA asserts, that the median is less affected by extreme values, and therefore is
considered more useful when there are outliers or extreme values that range over orders of
magnitude. In the context of Yucca Mountain, this aspect of the median clearly has utility.
Past Yucca Mountain performance assessments have often shown mean values near the 95
percentile of the output distribution - clearly an indication that extreme values are greatly
affecting the mean. (Comment 0298-16)
21.	Using the method of mean dose distribution during the first 10,000 years means that
large numbers of people would receive doses far higher than 15 millirem/year, with
proportionately higher risks for cancer. To make matters worse, in the period beyond
10,000 years, when the EPA switches from the mean dose distribution to assess regulatory
compliance to a median dose distribution, half of the radiation scenarios could result in
doses vastly exceeding 350 millirem/year. In fact, using the median dose distribution
method, the EPA introduces a 'sky is the limit' formula for half of the people above the
median where there is no maximum upper limit for exposure. This median dose distribution
method for risk assessment is so flawed that it has been rejected by scientists worldwide.
Under the new EPA rules, the median dose analysis method would allow significant
numbers of people to be exposed to doses that could statistically produce a 100% chance of
inducing cancer. (Comment 0301-5)
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22. The use of the median to set a dose limit from a combined distribution is inappropriate.
The best estimate of the mean dose (give all uncertainties) would be considerably higher
than the median. The 95th percentile dose of about 2 rem per year would create a lifetime
fatal cancer risk for women of about 1 in 10 and a cancer incidence risk of about 1 in 5.
This would make the proposed standard statistically about like Russian roulette rather than
a radiation protection rule at least for some people.
The EPA has justified the use of the median by saying that it does not want the high
values of dose to affect what it calls the "central tendency" of the distribution. Specifically,
it notes that "In fact, for early occurrences of disruptive events (human intrusion or igneous
intrusion), DOE assessments show that at some periods of time the arithmetic mean of the
projected doses can exceed the 95th percentile of the distribution of TSPA [Total System
Performance Assessment] results."
However, what the proposed rule dose not accurately take into account is that over
the time periods of actual interest to the standard (i.e. less than 10,000 years and between
100,000 and 1 million years) the projected dose distributions are well behaved with the
95th percentile larger than the mean which is, in turn, larger than the median of the
distribution. Specifically, for times less than 10,000 years the peak 95th percentile dose for
the proposed action is more than seven times higher than the peak mean dose while for
times out to one million years the peak 95th percentile dose is more than four times higher
than the peak mean dose. Reading off the graphs of projected doses in the DOE Final EIS,
we can also estimate that the peak median dose at long times will be about a factor of three
or four less than the mean.
The well behaved nature of the distributions of projected doses over both short and
long times is due to the fact that the peak doses are not dominated by "disruptive events,"
but by the natural processes of water infiltration, waste package corrosion, and radionuclide
transport to the biosphere. There is thus no scientific justification for accepting the use of
the mean for times less than 10,000 years as representative while rejecting the mean dose at
very long times. This conclusion is supported by the ICRP's Radiation Protection
Recommendations as Applied to the Disposal of Long-lived Solid Radioactive Waste, which
states that
As general guidance, the Commission considers that its recommendations on the
estimation of exposures in Publication 43 [.Principles of Monitoring for the
Radiation Protection of the Public] apply. The Commission therefore continues
to recommend that exposures should be assessed on the basis of the mean
annual dose in the critical group, i.e. in a group of people representative of those
individuals in the population expected to receive the highest annual dose, which is a
small enough group to be relatively homogeneous with respect to age, diet, and
those aspects of behaviour that affect the annual doses received.
In making use of different statistical measures for the dose limits, the proposed rule
increases the disparity between the level of protection provided to distant generations
compared to the present generation. Already the 350 millirem per year dose limit for times
greater than 10,000 years is more than 23 times the 15 millirem per year dose limit for
times less than 10,000 years. Taking into account the additional difference introduced by
the choice of statistical measures would make the long-term dose limit about 70 times or
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more greater than that which is considered acceptable today. We recognize that the process
of calculation is probabilistic and, therefore, there cannot be guarantees for everyone in the
literal sense. But, if a statistical approach is used for the long-term, there is a strong case to
be made that, whatever the value of the standard, the part of the probability distribution for
the dose limit should not be the median or even the mean, but the 95th or 99th percentile,
so that the vast majority of the population can be assured of protection. We recognized that
the DOE projections of dose estimates are the result of Monte Carlo realizations and do not
directly represent doses to fractions of the population. However, if the median of such
realization is 350 mrem per year, the uncertainties in the parameters will create a
significant likelihood that a large portion of the population will be exposed to more than
that, and some exposed to much more. Given that the uncertainties at the high end of the
doses are significant, the mean exposure could be much higher, perhaps several times
higher, that the median. Hence, while considerably less than half the exposed population
would be expected to be exposed to levels several times higher than 350 mrem/year, the
risks to them would be very high indeed.
The large uncertainties at the high end can be interpreted as representing a
significant chance that a small proportion of the population would be exposed to high
levels or that there is a small chance that large numbers of people could be exposed to them
at the time that the highest doses would occur. The interpretation would depend on the
specifics of the scenarios that are being run. For instance, a 95 percentile value of peak
dose of about 2 rem per year, which can be inferred from official DOE and contractor
estimates, could create great risk a small minority of exposed people. For women exposed
to this level of radiation it would create lifetime fatal cancer risks would 1 in 10 and
incidence risk would be about 1 in 5. This would make the proposed standard statistically
about like Russian roulette rather than a radiation protection rule at least for some people.
On the other hand, it can be interpreted as a small chance of creating very large risks for
large numbers of exposed people, which is also unacceptable. (Comment 0314.1-6)
23.	To make matters worse, EPA's 350 mrem/yr figure is not a maximum permitted dose to
the public, but rather a median dose, meaning that 50% of doses would, be higher than 350
mrem/yr. Large numbers of people would, under this proposed rule, get doses far higher
than 350 millirem/yr. EPA, proposes changing from the mean dose (add all the individual
doses and divide by the total number of doses to arrive at the average, or mean dose, thus
including very high doses in the mean) after 10,000 years to a median dose (the middle
dose value, with an equal number of dose values above and below it - meaning that very
high doses are simply disregarded, no matter how high they are) .
According to Dr. Robert Gould, chair of the security committee of Physicians for Social
Responsibility, "the sky's the limit" as to how high doses could go, for incredibly there is
no upper limit for the half of the exposures that would be above the median. These higher
doses would carry proportionately higher health risk. (Comment 0324-3)
24.	In DOE's Yucca Total System Performance Assessment for Site Recommendation, at
the time of peak dose (after the waste packages corrode and fail), the mean dose of the
many computer simulations is about 600 mrem/yr, whereas the median dose is about 200
mrem/yr. Yucca would not meet a standard that required the mean to be less than 350
mrem/yr, but would if the median were used. EPA's use of a 350 mrem/yr median dose
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limit is thus a transparent attempt to keep Yucca "licensable," despite its clearly unsuitable
geology. A median of 350 mrem/yr results in doses of 2,000 mrem/yr (2 rem/yr) to the 5%
of people most exposed; over a lifetime of such exposures, one in five women would
contract cancer from Yucca's leaking wastes. This is nightmarishly unacceptable.
(Comments 0324-4 and 0324-27)
25.	Just as with the magnitude of the dose, the EPA has chosen to require the arithmetic
mean expected dose of ensemble calculations for periods up to 10,000 years, but after
which the median expected dose is to be used. The inconsistency is not well explained; the
reasoning here does not mesh. Why not use the same method for all times? It appears as
though your agency is trying to be consistent with the National Academy of Sciences
recommendation on one hand, which clearly states; "We recommend that the mean values
of calculations be the basis for comparison with our recommended standards." (1995 NAS
Report p. 123), and on the hand satisfy the "needs" of the DOE to allow higher doses for
compliance after 10,000 years. By using the median, the bar of what DOE must
demonstrate is lower; by as much as 300 mrem/yr from the 2001 calculations. What is the
EPA up to? (Comment 0328-2)
26.	EPA should refine their median criteria to further address low probability uncertainties
and inherent conservatisms that exist in DOE and NRC dose projection methodologies.
(Comment 351-5)
27.	The Department agrees that for projections to time of peak dose, it is appropriate and
sensible to use a measure of repository safety based on the central tendency in the
distribution of calculated doses that is not strongly influenced by high- or low-end
projections that represent low probability situations. The Department considers that the
choice of the median instead of the geometric mean is a policy consideration, clearly within
EPA's scope, and the Department supports its use. (Comment 0352-32)
28.	It is well understood that the arithmetic mean is very sensitive to the largest values (the
extreme values) of the data set it is used to represent and thus can give a very distorted
picture of what is really happening if the distribution under consideration is skewed to the
high side. In such cases, one or a few very large data points can effectively dominate the
value of the arithmetic mean. This is precisely the situation with very long-term projections
of repository performance.. .Lognormal distributed data are biased toward extreme values
and, accordingly, these extreme values have the potential to dominate the estimate of the
mean. This is easily seen in plots of the dose rate... where the results are clearly lognormal,
and span 5 to 10 orders of magnitude. In a Monte Carlo realization, each realization has the
same probability of being correct.. .Consider, for example, a point in time on such a curve
where the upper and lower extreme values are 1,000 mrem/yr and 0.001 mrem/yr
respectively. These points have an equal probability of being correct; however, if an
arithmetic mean is used as the measure of compliance, the upper extreme has nearly one
million times the influence on the value of the arithmetic mean as does the lower
extreme.. .The geometric mean is the statistically correct measure of central tendency for
lognormally distributed data. Unlike the arithmetic mean, the geometric mean mitigates the
dominating effect of high extreme values. It simply is not possible to use the statistics of an
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arithmetic distribution, that is, the arithmetic mean, to deduce meaningful insight about the
central tendency of any data that are lognormally distributed.. EPA argues that undue
influence on the geometric mean by very small calculated doses is a basis for using the
median instead. However, small or zero results do have statistical meaning, and can be
accommodated in a number of ways for purposes of determining a geometric mean.. .In any
case, the use of a median value as proposed by EPA is a more realistic measure of central
tendency than is the arithmetic mean for lognormally distributed information and
accomplishes the aim of defining a measure of central tendency for lognormal results. It is
a reasonable substitute for the geometric mean for these types of distributions, since it
insulates the measure used for compliance purposes from the undue effects of extreme
values in the same way as the geometric mean. The Department considers that the choice of
the median instead of the geometric mean is a policy consideration, clearly within EPA's
scope; and the Department supports its use. (Comment 0352-33)
29.	The Department also concurs with the use of the arithmetic mean for the 10,000-year
standard. The Department notes that EPA chose the arithmetic mean rather than the median
for the original 10,000-year standard because it was the more conservative of the two
measures. While it might be appropriate to use a more conservative measure for the initial
10,000 years, such conservatism is unwarranted at the time of peak dose. Use of the median
instead of the geometric mean as the compliance test for dose at time of peak risk is clearly
consistent with EPA's emphasis on the importance of reasonable expectation as the
standard of proof of compliance.. .The extreme values result from realizations in which
many of the parameter values are drawn from the extreme tails of the probability
distributions. Yet the tails are often the part of the distribution about which there is least
confidence, so that a measure such as the mean, which can be dominated by such extreme
values, is a more uncertain measure than the median. (Comment 0352-34)
30.	Failure to use an appropriate measure of central tendency to describe results of
simulations involving lognormally distributed parameters would not be consistent with
EPA's direction to use realistic approaches to model the site performance. (Comment
0352-35)
31.	In issuing the final rule, EPA should clarify that the statement made in promulgating
Part 197 in 2001, ".. .the fundamental compliance measure consistent with a literal
mathematical interpretation of [reasonable expectation] would be the mean value of the
distribution of calculated doses," is not applicable at the time of peak dose. (Comment
0352-37)
32.	The result of calculating the 350 millirem/year standard using the median is that it is 70
times less stringent than the 15 millirem/year standard which is calculated using the mean.
The radiation rule will affect thousands of generations into the unknown future. We don't
know the future, but the farther out in time we go, the more conservative we should be.
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EPA argues that because it is such a long time, a weak standard is better than none. We
believe that because the future is unpredictable, it is important that the standard contain
conservatism so that the repository system can be judged based on its ability to contain the
waste in thousands of years. The way to do that is to adopt a standard that contains that
conservatism. Revising the radiation standard by switching from the mean to the median is
less conservative, is less protective, and is not acceptable. (Comment 0353-8)
Response to Issue A:
Most comments on this topic opposed our proposal to use the median of the distribution of
results as the statistical measure of compliance for the peak dose between 10,000 and
1 million years, primarily because it is expected to be lower than the arithmetic mean
(Comments 0186-9, 0186-10, 0186-11, 0186-12, 0226-11, 0226-12, 0226-13, 0263-6,
0263-9, 0263-11, 0263-20, 0268-3, 0294-3, 0296-3, 0301-5, 0314.1-6, and 0353-8). We
also received some comment supporting our proposal as an appropriate way to address the
difficulties in projecting doses for periods up to 1 million years (Comments 0298-16, 0352-
32, 0352-33, 0352-34, 0352-35, and 0352-37). We proposed to use the median for the
period between 10,000 and 1 million years as a way to acknowledge the greater
uncertainties in dose projections over that time frame and to lessen the potential for a small
number of very high projected doses to have a disproportionate effect on the overall
outcome, which is more likely to be seen when using the arithmetic mean. We wanted the
statistical measure to reflect the "central tendency" of the dose projections, which we
believed would be a fair representation of disposal system performance over the time
frames in question. We considered the relative merits of the arithmetic mean, geometric
mean, and median in meeting this goal, and proposed the median as the best of the three.
See 70 FR 49041-49046 of the proposal for this discussion.
After further consideration of comments and the NAS Report (see Issue B of this section),
however, we are changing our approach to the determination of compliance for the post-
10,000-year standard at Yucca Mountain. We will require NRC to use the arithmetic mean
of the distribution to determine compliance at all times. Thus, while there are substantive
issues raised by commenters concerning use of the geometric mean or median as the
appropriate statistical measure to determine compliance, given that the Agency, consistent
with the recommendation of the NAS, has adopted the arithmetic mean as the appropriate
statistical measure, we find that the technical bases of those comments do not require
response.
Section 7 Use the Mean or Median?
Issue B: NAS recommendation of the mean
1. For several reasons, this shift to the median is flawed. First, the NAS expressly
recommended the use of the mean. Second, using the median is inconsistent with EPA's
own past and present statements and practice, and EPA has offered no rational explanation
for the shift. Third, EPA's approach is scientifically and statistically unsound. Finally, use
of the median would allow a grossly unsafe site to be licensed; though DOE's current
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modeling projects that the median dose will be below 350 millirem/year, 42 percent of the
modeling runs appear to exceed that number. See Appendix A, at 8. No site that has a 42
percent chance of failure can ever be considered adequate. [T]he NAS could not have been
more clear: "We recommend that the mean values of calculations be the basis for
comparison with our recommended standards." NAS Report at 123 (emphasis added).
Since EPA's rule must be based upon and consistent with the NAS's findings and
recommendations, that recommendation mandates the use of the mean. Yet EPA has not
only failed to implement that recommendation; it has pretended it doesn't exist. EPA falsely
claims that "NAS in its recommendations did not speak explicitly to any particular
performance measure to be used in determining compliance with regulatory standards." 70
Fed. Reg. at 49043. That obviously is not true. In proposing to use the median rather than
the mean, EPA also would deviate from the practice of the NRC, which in its prior Yucca
Mountain rule also specified that the mean would be used. In responses to comments, the
NRC explained why the mean was the appropriate measure. 66 Fed. Reg. at 55752
(November 2, 2001). (Comment 0226-10)
2.	The Technical Basis for Yucca Mountain Standards, on page 75, explicitly recommends
that mean values of calculations be the basis for comparisons with recommended standards.
Despite the court's ruling that the NAS recommendations be followed, the EPA has
deliberately elected to disregard this recommendation at times greater than 10,000 years
where the median value is being proposed for comparison to the standard. Will EPA justify
its position on ignoring the NAS recommendation on the use of the mean value?
(Comment 0263-8)
3.	Although NAS did recommend use of the "mean values of the calculations" we find that
use of the median for longer term calculations would not be inconsistent with those
recommendations. NAS recognized the need for EPA to apply policy judgments in matters
such as these, stating "We acknowledge that determining what risk level is acceptable is
not ultimately a question of science but of public policy." Consistent with this philosophy,
EPA should use its discretion, as a matter of policy, to assure that the mathematical
determinant of risk is calculated in a manner that is not overly subject to extreme values.
EPA's specification of use of the median value for calculations beyond 10,000 years is an
appropriate use of agency discretion. (Comment 0298-17)
4.	The NAS "recommended the mean values of calculations to be the basis for the
comparison with our recommended standards." The mean gives equal weight to all
scenarios, and gives the best estimate of the expected dose. The scientifically appropriate
way to weigh uncertainty is to select scientifically based distributions of the uncertainties
of the most significant individual parameters used in the modeling, and then sample these
uncertainties using well known modeling techniques. It is scientifically unsound to skew
the final results by using the median dose as a benchmark for comparison against a
regulatory limit. (Comment 0311.1-9)
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5. It is appropriate for EPA to address the fact that the Committee report recommended use
of the mean as the test for compliance.. .In the absence of any clearly stated scientific or
technical basis in the Committee report for use of the arithmetic mean, that
recommendation should be viewed as a policy suggestion rather than as the kind of
technically based finding or recommendation that the Energy Policy Act of 1992 was
seeking from the Committee, and should not constrain EPA's ability to establish policy for
the protection of public health and safety. The Committee's statement is in a section
comparing the Committee recommendations with the 10,000-year standard at 40 CFR Part
191. It is important to note that the report contains no discussion of the technical issues
concerning the choice of the measure of central tendency to use for compliance
comparisons, or, more importantly, crucial recognition of the inherently skewed or
lognormal nature of the peak dose performance assessment results that has so much bearing
on the choice of the appropriate measure. EPA proposed rule is correct in concluding that a
different measure is appropriate for assessing performance at time of peak dose for
technical reasons. Further, much of the discussion of the use of the mean in the proposed
rule concerns homogeneity in assessing mean group risks. If these data were lognormally
distributed, then the geometric mean would be the appropriate statistical measure for
assessing central tendency there as well. (Comment 0352-36)
Response to Issue B:
Comments 0226-10, 0263-8, and 0311.1-9 focused on a statement by the NAS committee:
"We recommend that the mean values of calculations be the basis for comparison with our
recommended standards." (NAS Report, p. 123) After consideration of these comments
and further review of the NAS Report, we agree with the commenters that specification of
the arithmetic mean as the appropriate statistical measure by which to determine
compliance with the radiation protection standards at Yucca Mountain is consistent with
the language in the NAS Report. We did receive some comments making the case that our
proposal to use the median could be consistent with the NAS statement, in the sense that
the committee recommended the same compliance measure used in 40 CFR part 191,
which covered only 10,000 years, but did not show any appreciation that technical or
policy considerations might come into play if the distribution of projections covering
hundreds of thousands of years differed in significant ways from those shorter-term
projections (e.g., if projections are extremely skewed or otherwise suggest the arithmetic
mean would not be representative of expected performance) (Comments 0298-17 and
0352-36). These comments also suggested that the median could be consistent with use of
the term "expected value" as used by the NAS committee because the committee intended
that the compliance assessment not be overly driven by a limited number of high-end
results. Given the express mandate of the EnPA, however, that our standards must be
"based upon and consistent" with the recommendations of the NAS, we decline to adopt
this reasoning.
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Section 7 Use the Mean or Median?
Issue C: Other mean/median comments
1.	Discussions in Section II.C.5 about normal distributions seem to me to be largely
irrelevant, because I don't see how projected outcomes of waste disposal at Yucca
Mountain will be normally distributed if reasonable probability distributions of input
parameters are used. It seems to me that projected outcomes will closely resemble
lognormal distributions. (Comment 0186-24)
2.	There are two major problems with the proposed metrics, the mean and the median: a)
these metrics have been shown by numerical experiments to usually under predict the
actual dose to the public, and b) using current state of the art methods, these metrics are
unstable and cannot be reliably predicted. On the whole, the peak of the mean metric
chosen by EPA tends to underestimate the actual received dose. The median metric
provides even lower estimates of risk than the mean and is thus even more problematic.
Other, easy to regulate metrics such as the mean of the peak of each realization, for
example, are more stable and provide a more accurate prediction of the actual received
dose. Please revise the regulation to use more stable and robust predictors than the mean or
median of the realizations. EPA should not mislead the public by stating that a metric
which can be reliably predicted is desirable and then turn around and choose metrics (mean
and median) which are demonstrably unpredictable using current state of the art methods
and which tend to underestimate dose. (Comment 0202-1)
3.	However, the International Peer Review (IPR) of the Yucca Mountain Project expressed
concern that even using the mean value of a set of realizations could be subject to
systematic underestimation of the real expected value due to the phenomenon of risk
dilution. If such risk dilution is considered a problem with the use of the mean value by the
IPR, then it must be a much more serious compliance problem with the use of the median.
The EPA should only use the mean value as a measure of compliance to ensure future
generations are protected. In addition, the EPA should acknowledge the possibility of risk
dilution and mandate how the effect will be mitigated (or explicitly direct the NRC to do
so). (Comment 0263-10)
4.	The EPA claims it is retaining the FEP cut-off probability of 10"8 per year in the post
10,000 year standard. This is incorrect if the median is used as a measure of compliance.
Consider a low probability event with a potentially large consequence such a volcanic
eruption through the repository. Ignoring the dilution due to the finite duration of the
consequences (as discussed in 10b), for the event to be considered using the metric of the
median value of the realizations would require that at least half of the probabilistic
realizations include the event, i.e., the expectation of having no events over the million
years must be less than 0.5. Using Poisson statistics, this implies that events with a rate of
less than 6.9x 10"7 per year automatically cannot influence the median (i.e., fewer than 50%
of realizations would, on average, include the event) and as such are effectively screened
out at a much higher probability level (6.9x 10"7 per year ) than 10"8 per year as claimed.
The EPA needs to propose an alternative to the use of the median such that the required
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low probability events are taken into account. This could be done be replacing the median
(i.e., the 50%ile) by the mean value or the 99%ile (or possibly, with lots of arm waving, at
the 95%ile) of all realizations. Such a replacement would be in line with normal statistical
inferences where results subject to uncertainty are given at the 99% (or 95%) confidence
limit. (Comment 0263-17)
5.	EPA should refine their median criteria to further address low probability uncertainties
and inherent conservatisms that exist in DOE and NRC dose projection methodologies. A
possible way would be to set the post 10,000 year criteria to a 25% probability and median
dose at two or more times the standard dose criteria. Although such an approach has not
been used before, neither have numerical standards ever been required beyond 10,000 years
before. (Comment 0264-6)
6.	. . . with respect to the specific questions posed by EPA on elements of the proposed
standard (e.g., median vs. mean; treatment of features, events, and processes; Reasonably
Maximally Exposed Individual) Duke endorses the comments provided by NEI on the
behalf of the nuclear industry. (Comment 340-2)
Response to Issue C:
Several comments on this topic were technical in nature and raised points that are not
necessarily obviated by use of the mean instead of the median. We will address them only
briefly here. Comment 0263-10 raises the issue of "risk dilution" and urges us to explicitly
direct NRC how to address this potential. "Risk dilution" in this sense refers to the
possibility that uncertainty in parameter value distributions may be addressed by
deliberately making those distributions broader to increase confidence that the distribution
includes all of the "actual" values (i.e., the distribution is made to encompass a wider set of
values), which is often considered the "conservative" approach. The commenter believes
in some cases this could result in more optimistic (i.e., lower) dose estimates. The
commenter refers to the conclusions of the IAEA-NEA International Peer Review of the
TSPA-SR (pp. 55-56) in asserting that the effects should be more serious if the median is
used as the statistical measure. We do not believe this would necessarily be the case, for
the same reason that the arithmetic mean is more affected by extreme values than is the
median. In any event, we believe it is NRC's responsibility to examine DOE's data and
assumptions to ensure that its performance assessments are appropriate and do not rely on
overly conservative or overly optimistic parameter values. We believe proper
implementation of the principles of "reasonable expectation" will limit the potential for
"risk dilution" of this type, particularly the emphasis on the "full range of defensible and
reasonable parameter values."
The same commenter (0263) disputes our statements that the probability threshold for FEPs
in our proposal is the same for the entire 1 million-year period. The commenter believes
the use of the median would actually result in a threshold that effectively excludes the
effects of some low-probability, high-consequence FEPs from consideration in the post-
10,000-year performance assessment results. The commenter seems to conclude that such
a FEP must be in at least 50% of the realizations to "influence the median." However, we
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must point out again that a FEP with annual probability of 1 in 100 million (10"8) would not
be likely to appear in 50% of realizations, regardless of the compliance measure selected.
This annual probability translates to a 1% chance of occurrence within 1 million years, well
below 50%. Using probabilistic sampling methods and assuming a series of 300
realizations (based on previous DOE efforts), such a low-probability FEP would be likely
to be present in only a few realizations at most (and possibly in none of them).
Comment 0202-1 suggested an alternative measure for comparison to the dose standard.
This commenter believes neither the arithmetic mean nor the median provides a sufficiently
stable or accurate measure of disposal system performance. The commenter suggests using
the "mean of the peaks," which involves averaging the peaks (maximum doses) of the
individual realizations, rather than the "peak of the mean," which averages the individual
realizations at each time step and identifies the maximum of that curve. The commenter
believes the peak of the mean is less stable because it is more affected by uncertainty in
parameter values, which tends to make the individual peaks less coincident and has the
overall effect of lowering the mean (if there is high confidence that the peak will occur at a
specific time, the "mean of the peaks" and "peak of the mean" would be the same;
however, if the peaks are widely separated in time, each peak may be averaged with many
"non-peak" values, giving a lower overall estimate compared to the average for all
individual peaks). For similar reasons, this commenter also believes the peak of the mean
is more susceptible to "risk dilution," as discussed above. The mean of the peaks is less
affected in this situation because it does not depend on the timing of the individual peaks.
The mean of the peaks may be seen as preferable in situations where a considerable number
of individual realizations exceed the regulatory standard at some time (or in an extreme
case, where they all do), but the mean dose curve remains below the standard. However,
we would be concerned that such a conclusion would credit each realization with a level of
precision that is difficult to defend, given the many factors contributing to uncertainty in
long-term projections (see Section 6 of this document for more discussion). We believe it
is more defensible to consider the projections in an aggregated fashion. In addition, we
believe NAS intended the peak of the mean be used, as indicated by its recommendation to
assess compliance with the standard "at the time of peak risk." (NAS Report p. 2) There is
no "time of peak risk" if the mean of the peaks is the measure of compliance.
Regarding the accuracy of the relative measures, reference to the cited PhD dissertation
(Docket No. EPA-HQ-OAR-2005-0083-0098) indicates that "accuracy" is determined by
comparison to a "nominal" case in which a single deterministic realization of the
hypothetical system is conducted using average parameter values. It is not clear that this
"nominal" case should be considered the "expected" performance, nor does it capture the
range of system performance that is the objective of probabilistic assessments. To say that
the peak of the mean "consistently underestimates" risk implies that the nominal
deterministic case provides the best representation of overall system risk, which may not be
the case.
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Further, while it may provide useful information, we have concerns as to whether the mean
of the peaks can be considered to correctly represent risks to an exposed individual. While
the nature of the calculation makes it likely to be higher than the peak of the means (unless
the two are identical), we note the referenced dissertation statement that "the mean-of-the-
peaks metric does not necessarily correctly portray risk in terms of factoring in both the
probability and consequences of the exposure to specific individuals living in the future.
This metric averages the peak doses, even though those peak doses may be widely spaced
over time and beyond the expected life-span of a single individual." (EPA-HQ-OAR-2005-
0083-0098, p. 6) By contrast, "the peak-of-the-mean metric factors into the estimate of risk
both the probability that a particular individual will be exposed and the extent the
individual is exposed." The peak of the mean approach has the advantage of being a more
realistic description of the range of potential receptor dose rates at all points during the
compliance period, whereas the mean of the peaks approach cannot be considered to reflect
the dose potential for the RMEI at any particular time since it averages peak dose rates that
are separated in time. From a regulatory perspective, because it represents the evolution of
the entirety of the disposal system over time, the peak of the mean may provide a more
meaningful basis for decision-making. At each point in time, the progression of the
individual realizations and the mean dose curve can be more easily viewed in relation to
one another as indicative of "expected performance." The mean of the peaks, on the other
hand, relies on the combination of specific points of distinct realizations that may make it
more difficult to relate to the overall safety of the system, and the remainder of each
realization is of no consequence in the evaluation of that system. Except perhaps in the
extreme situation where all (or substantially all) of the realizations exceed the regulatory
standard, it is not clear exactly what information the mean of the peaks conveys about the
disposal system as a whole. See also Section 2, Issue M of this document for some
discussion of this topic.
Comment 0264-6 encourages us to go even further in addressing uncertainties and
conservatisms, believing this will counteract NRC tendencies to take a very conservative
position in licensing. The commenter appears to be suggesting that a median dose of "two
or three times the standard dose criteria" (which we interpret to be 15 mrem/yr) would be
sufficient if the probability threshold for FEPs were changed to only consider FEPs with a
25% chance of occurrence (1 chance in 4). It is unclear whether this would be an annual
probability or a cumulative probability over the 1 million-year period. However, we
believe important FEPs would be excluded from the analyses by such a screening level,
which would be inconsistent with the purpose of a probabilistic analysis. We believe it is
important to consider FEPs shown to have occurred at the site in the relatively recent
geologic past (past few million years) in order to have a sense of the natural processes and
events that might affect disposal system evolution.
We further disagree that the probability threshold for FEPs should be connected with the
statistical measure of compliance, and that the selected statistical measure gives
inappropriate emphasis to low-probability/high consequence FEPs. Connecting these two
concepts could easily introduce bias in setting up the performance scenarios if the analyst
was attempting to predetermine the results of probabilistic assessments to show
compliance. We have taken care to define the probability threshold independent of any
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consideration of the final performance measure to expressly avoid the possibility of
introducing such a bias. We believe performance scenarios should be developed,
considering only the FEPs relevant to the site, and constructed accordingly, not with an eye
on the eventual compliance measure that will be applied to the results of the assessments.
The direction from NAS concerning low-probability /high consequence events advised that
the standard should be designed such that it "does not rule out an adequately sited and well-
designed repository because of highly improbable events." (NAS Report p. 28) We
interpret this as clearly indicating that low-probability /high consequence FEPs could
reasonably be expected to exist for the repository setting over time, but that they should be
kept in perspective within the set of identified FEPs and not overly emphasized in
performance assessments or compliance decision-making. In our proposal, we explained
how lowering the probability threshold for FEPs to include events now considered "very
unlikely" would create unreasonable and unworkable consequences for the performance
assessments over the period of geologic stability. (70 FR 49049) Low-probability FEPs,
but those still above the threshold, are included in probabilistic assessments, but their
consequences are weighted according to their probability and therefore placed in
perspective relative to the higher-probability FEPs that constitute the bulk of the expected
performance scenarios.
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Section 8 Climate Change
1.	Who knows what future climate change may happen to affect these things. The
uncertainty is all too great to accept. (Comment 0105-5)
2.	EPA allows the use of stylized scenarios for climate variability, that are simplified to a
level that is consistent with the equally stylized assumptions that must be made for human
behavior over extremely long time periods. This approach would be required for the
analysis of most other very-long term hazards. (Comment 0174-6)
3.	Because predicting future climate over both in the short and long run is an inexact
science at best, EPA has written a rule to permit DOE to make, for compliance purposes,
the one future compliant assumption we know not only to be wrong but absurd.
Future climate at Yucca Mountain is important because it strongly influences the
rate at which waste containers and other metal barriers corrode. EPA and its new proposal
permits the assumption that, after 10,000 years and out to one million years, the climate at
Yucca Mountain can be assumed to remain unchanged for the purpose of those compliance
determination.
Enough is already known about past variation in climate to see not only the
absurdity of the assumption, but also to put some limits on the magnitude of changes they
expect in the future.
Obviously, EPA can do better than they allow the assumption the climate will
remain unchanged after the next 10,000 years. The fact the Agency has not done so is
additional evidence of assisting DOE and of EPA's clear intent to pave the way for Yucca
Mountain licensing rather than establish legitimate and truly protected health and safety
regulations. (Comment 0209.7-8)
4.	EPA does know that wetter periods will occur at some future time, and we can analyze
how the repository will perform when those periods do occur. EPA suggests that because
the site geology will have a dampening effect on climate changes, masking the effects of
changes several hundred years or less in duration, changes of longer-lasting duration also
need not be analyzed. This also is inapposite. As indicated by the NAS language that EPA
cited, this dampening effect should transfer the focus to longer-term climate changes (for
example, glacial states that might last for thousands rather than hundreds of years). NAS
Report at 93. The short-term dampening effect provides no reason for ignoring long-term
changes. (Comment 0226-87)
5.	As the NAS report and EPA's own past statements indicate, significantly wetter climates
will occur and will adversely impact repository performance. In mandating that those
conditions be assumed out of existence, EPA's proposed rule would ignore the NAS's clear
recommendation. Dr. Thorne indicates (Appendix E), EPA's specification that only
constant climate conditions may be considered ignores the possibility that other factors
influenced by global warming will have a substantial effect on deep percolation of water
into the repository. (Comment 0226-88)
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6.	EPA makes three very broad assumptions about climatic and hydrologic behavior at
Yucca. These are that (1) future climatic conditions at Yucca can be bounded by the
observed range of conditions over past glacial-interglacial cycles; (2) consideration of
climate changes after 10,000 years will introduce uncertainties that do not exist in the
period before 10,000 years; and (3) only long-term average responses of the system to
changes in infiltration are of relevance. However, as is explained in detail in the report
attached in Appendix E, prepared by Dr. M. C. Thorne with input from eminent
climatologists Dr. Jonathan Overpeck, Dr. Thomas Wigley, and hydrologist Dr. Howard
Wheater, these conclusions are not adequately substantiated by EPA. The full Appendix E
must be considered. The effects of different climates after 10,000 years can be better
investigated using current and developing techniques that would command substantial
support in the scientific community. Therefore, EPA's climatic bounding and infiltration
conclusions are at best premature, and at worst unsound. Certainly, these effects are not
appropriately the subject of advance specification by rule. See Climatic Considerations
Relevant to the Draft EPA Rule, by Dr. Michael C. Thorne. Moreover, as Dr. Thorne points
out, EPA has unreasonably failed to consider the impact of anthropogenic releases of
carbon dioxide on climate and infiltration.
As a result, EPA's assumptions about climate and infiltration over the long term at
Yucca are arbitrary and capricious. (Comment 0226-115)
7.	The writing supporting the proposed rule seems to equate the situation in some European
countries with what's expected at Yucca Mountain and uses the approach some of these
countries are proposing for very long timeframe performance calculations as models for
how similar calculations should be done for the US repository. In countries like Finland
and Switzerland, these countries will be buried in alpine and continental glaciers, whereas
Yucca Mountain will simply be wetter than presently. The Yucca mountain site would be
little different than today - only with increased precipitation. The approaches from other
countries don't offer themselves as models for the US repository, and I believe that you are
misusing the approaches as models. (Comment 0258-1)
8.	We commend EPA for proposing a stylized approach to addressing climatological FEPs
beyond 10,000 years. Such an approach is necessary to bound speculation about potential
future climate states. However, we recommend that EPA take this approach one step
further by specifying that climate should be assumed constant over the beyond-10,000-year
period instead of stipulating thatNRC define values to represent future climate change.
Human behavior and climate are inexorably linked. To vary one and not the other will
create inconsistencies in the analysis that will lead to artificial results not representative of
any conceivable future population. For example, why would the future RMEI continue to
maintain his crops almost entirely with groundwater (as does today's present day rural-
residential desert dweller) when those crops might already be receiving significant amounts
of rain due to climate change to a wetter environment? Our argument that climate should be
held constant at the present-day state is supported by the knowledge that today's relatively
dry climate is a conservative approximation of future climates, because it is so dry, forcing
relatively high dependence on groundwater. Groundwater is by far the most significant
contributor to potential future radiation exposures. The assumed present-day RMEI is
virtually 100% dependent on groundwater. The extreme unlikelihood that an individual in
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any future climate state could be more dependent on groundwater would make a regulatory
specification of present-day climate highly conservative. (Comment 0298-20)
9.	Furthermore, recent EPRI global climate modeling work suggests that anthropogenic
greenhouse gases may delay the onset of the next glaciation cycle by 130,000 to more than
500,000 years. Hence there is even more uncertainty about whether specifying higher
infiltration rates as representative of long-term average climate. Given both this new
information and the reasons stated above, we do not agree with EPA's recommendation to
NRC that "a doubling of today's average annual precipitation beginning at 10,000 years
and continuing through the period of geologic stability would provide a reasonable
scenario." Fixing the long-term climate to that of the present day would be more
appropriate. (Comment 0298-21)
10.	A range of possible climate states, rather than constant climate conditions assumed for
the next 1 million years should be required to be incorporated in the performance
assessment. (Comment 0302-18)
11.	EPA claims that exposures to contaminated groundwater would be less likely if the area
were to become wetter in the future, because surface water would become more available
and reduce use of the groundwater (even if the groundwater is more contaminated as a
result of increased precipitation and water infiltration into the repository). Yet, EPA
concedes that a wetter climate means that more people are likely to live closer to the site
and, thereby, use groundwater closer to the site. This alone increases the risk posed, and
must be taken into account. (Comment 0302-19)
12.	The greater the effective moisture, the higher the risk of infiltration or recharge. Hence,
if climate change increases groundwater infiltration into the repository, this may cause an
increase in radionuclide dissolution and higher release rates from the waste. Moreover,
because pollution includes any man-made or man-induced alterations of the radiological
integrity of water, such releases could cause direct violations of the Clean Water Act and
Safe Drinking Water Act. The four effective climate states each have a varying level of
effective moisture. With the exception of the monsoon climate state, the interglacial period
- modern-day Yucca Mountain - has a lower annual precipitation and higher annual
temperature than the stations selected to represent the other climate states. Hence, glacial
and intermediate climate states are predicted to be cooler and wetter than modern and,
therefore, would have more effective moisture and lower evaporation rates. Glacial and
intermediate climate states are the most important in terms of impending infiltration
because they have more effective moisture compared to the other climate states. Thus,
precipitation would be stored more easily under these conditions than under current climate
conditions.
This notion is supported by the National Academy of Sciences, and referenced by the
EPA in paragraph 8 of Section II.D.2.d.: "Change to a cooler, wetter climate at Yucca
Mountain would likely result in greater fluxes of water through the unsaturated zone."
These increased levels of infiltration threaten rates of radionuclide release from the
repository and subsequent transport to the water table. (Comment 0312.2)
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13.	In Section II.D.2.d. paragraph 3, the proposal references NAS statements concerning
climate speculation: "Although the typical nature of past climate changes is well known, it
is obviously impossible to predict in detail either the nature or the timing of future climate
change. This fact adds to the uncertainty of the model predictions." However, the present
docket underestimates uncertainties linked to the science of climate change. It is possible,
for example, that past climate cannot serve as an analog for future climates. Other notions
include aspects of the paleoecologic record such as reconstructing past climate and
resolution and timing of specific events in the past. In additions, human behavior might
greatly enhance chaotic behavior within the climate system. Indirect effects of human
activity on climate can simply be only speculated upon. There is also uncertainty in future
climate itself, perhaps past climate may not repeat in the future. Moreover, according to
Saxon Sharpe, the author of Future Climate Analysis - 10,000 years to 1,000,000 years
after Present and others, many linkages to climate change are not fully understood. For
example, connections with the El Nino Southern Oscillation (ENSO) cycles, solar
variability, increased atmospheric carbon dioxide, and ocean-atmosphere interactions are
unclear. Likewise, factors influencing the timing of climate cycles, the role and
mechanisms of global oceanic circulation, global effects of land use and land surface
alterations, and the role of biological processes are yet to be clearly defined in association
with climate change.
While EPA's evaluation of FEPs seems logical at first glance, many related
externalities are wholly ignored. While uncertainties such as astronomical activities are
screened out by probability, it is impossible to ignore FEPs that are not understood - such
as the indirect activity of human and other linkages to climate change, and future
temperature and precipitation values affecting repository behavior. (Comment 0312.3)
14.	EPA acknowledges that "it is possible to assume any number of scenarios of climate
over [1 million years]," yet the proposal recommends standards based off a "climate
scenario that assumes reasonable temperature and precipitation values," essentially
ignoring the myriad number of ambiguities presented. Future temperature and precipitation
values that may be considered "unreasonable" are disregarded. These "reasonable
expectations" may in fact be taken too lightly. As a result, model predictions used by the
EPA do not entirely characterize future climate conditions, and therefore misrepresent a
main, looming threat: radionuclide contamination into the surrounding water resource that
is used for domestic and agricultural purposes.
Future climate conditions can only be speculated upon and hence, future temperature
and precipitation values are unknown. Therefore, it is possible that conditions beyond
10,000 years (or less) may very well be unreasonable. Disregarding this view results in an
oversimplified assumption that undercuts the objective of EPA to protect public health and
the environment. Subsequently, the Clean Water Act and Safe Drinking Water Act are
undermined.
Section 301 of the Clean Water Act states that it is "unlawful to discharge any
radiological... agent, any high-level radioactive waste... into the navigable waters."
Further, the Safe Drinking Water Act maintains a 4 mrem/year Maximum Contaminant
Level standard for beta particles and photon emitters in drinking water. Although the
Yucca Mountain facility certainly does not intend to pollute the underlying waters with
radionuclides, and while the National Academy of Sciences concluded that "scientifically
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justifiable analyses of repository behavior over many thousands of years in the future can
be made," uncertainties unaccounted for - yet still associated with climate change - should
persuade the EPA to follow a precautionary principle in setting standards.
The EPA's failure to recognize the true ambiguity of climate change has the potential to
seriously undermine their model predictions. EPA should establish a precautionary
standard based not only upon "reasonable" climate scenarios, but upon conditions
reasonably unlikely as well. (Comment 0312.4)
15.	The impacts of future changes in climate should be taken into account explicitly in the
DOE's performance assessments including the consideration of periodic cycling through
different climate states on the performance of the isolation system. (Comment 0314.1-8)
16.	This treatment of climate change in the EPA's proposed rule is scientifically incorrect,
will tend to underestimate the impacts from the disposal of spent fuel in the repository, and
does not appear to be consistent with the recommendations of the 1995 National Research
Council review as required by federal law. In the executive summary to its Technical Bases
for Yucca Mountain Standard, the NRC committee stated that "We further conclude that
the probabilities and consequences of modifications by climate change, seismic activity,
and volcanic eruptions at Yucca Mountain are sufficiently boundable that these factors can
be included in performance assessments that extend over this time frame [one million
years]" Later in the report, the NRC committee elaborated on the treatment of climate
change that it felt should be included in the performance assessments and noted that recent
research has indicated that the past 10,000 years are probably the only sustained period of
stable climate in the past 80,000 years. Based on this record, it seems plausible that the
climate will fluctuate between glacial and interglacial states during the period suggested for
the performance assessment calculations. Thus, the specified upper boundary, or the
physical top boundary of the modeled system, should be able to reflect these variations
(especially in terms of
ground water recharge). Thus, the use of a constant value as proposed by the EPA would
not be consistent with the NRC committee recommendations that the "probabilities and
consequences" of future climates changes are sufficiently well understood to allow the
"variations" in water infiltration to be taken into account. In fact, the DOE performance
assessments as presented in the Final Environmental Impact Statement for a Geologic
Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at
Yucca Mountain, Nye County, Nevada published in 2002 already explicitly took into
account the variation in future climate changes in its prediction of doses out to one million
years. (Comment 0314.1-14)
17.	Beyond the issue of whether the proposed rule is consistent with the recommendations
of the National Research Council as required, the use of a constant or average infiltration
rate for the period from 10,000 to one million years is not scientifically valid and would not
accurately represent the impacts of climate change on the performance of the repository.
The response of the geologic system to increases in available water is not a simple linear
one in which increased infiltration rates lead to a proportional increase in water flux
through the repository. As summarized by Jane Long of the University of Nevada, Reno
and Rod Ewing of the University of Michigan in 2004 At present, there is no accepted
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conceptual model that explains the travel times and can consequently be used to infer the
flux. If climate change were to produce a larger influx of water, saturation in the mountain
could increase. Permeability under any proposed model increases nonlinearly with
saturation. Small increases in percolation flux could significantly increase fluid flow
through the repository horizon. This nonlinear response is one of the greatest
challenges in predicting the behavior of hydrologic systems over long periods.
(Comment 0314.1-15)
18.	The issue of climate changes is of significant importance to the predicted long-term
performance of the repository. The Total System Performance Assessment presented by the
Department of Energy in its 2002 Final EIS for Yucca Mountain included a consideration
of the transitions between future climate states, and found that the resulting dose
predictions were also cyclical and that "[t]he multiple peaks occurring 200,000 years or
more after repository closure are driven by transitions between climate states." For a sense
of the scale of these cyclical changes, the difference between the highest peak dose and the
lowest value before the next peak in the DOE predictions was roughly a factor of ten Not
unexpectedly, the DOE found that "[t]he peak annual individual dose usually coincided
with the occurrence of a wetter climate period." The use of a constant climate state over the
period beyond 10,000 years as proposed by the EPA would washout the important impacts
brought about by the changes between climate states and would tend to underestimate the
actual peak dose that would be expected from the repository. This underestimation would,
along with the use of the median dose, lead to even larger risks for distant generations
being possible under the proposed rule. This would further aggravate the issues of
intergeneration equity discussed in section one. The final rule issued by the EPA should
require the DOE to explicitly consider the long-term fluctuations in climate and to use
conservative assumptions about the timing and duration of wetter climate states given the
non-linear response of the transport models and the large influence of climate on the long-
term performance of the Yucca Mountain repository. (Comment 0314.1-16)
19.	Recent experimental studies on the growth rates of calcite and opal in the Exploratory
Studies Facility suggest that the deep environment is buffered from dramatic changes in
infiltration rates, even over time scales during which major pluvial events have occurred.
This supports EPA's proposal that the nature and extent of climate change should be
reasonably represented by constant conditions taking effect after 10,000 years to the time
of geologic stability. The Department also agrees that assuming water flow will increase as
a result of climate change is reasonable and appropriate. (Comment 0352-15
(supplemented from Comment 0396))
Response to Section 8:
As can be seen from the comments, there remains considerable debate about how
projected climate change over the next 1 million years will affect the Yucca Mountain
disposal system. We recognized and accepted this notion in the preamble to our proposal
(70 FR 49058), and argued that in light of the uncertainty involved in making a
determination of wetter and drier climate scenarios, a more effective and reasonable way
of considering how climate will affect the disposal system was through the use of a
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stylized scenario for the climatological FEP. We followed the direction of the NAS in
proposing this scenario. NAS stated the following with regard to climate change at Yucca
Mountain:
During the past 150,000 years, the climate has fluctuated between glacial and
interglacial status. Although the range of climatic conditions has been wide,
paleoclimatic research shows that the bounding conditions, the envelope
encompassing the total climatic range have been fairly stable (Jannik et erf.,
1991; Winograd et al., 1992; Dansgaard et al., 1993). Recent research has
indicated that the past 10,000 years are probably the only sustained period of
stable climate in the past 80,000 years (Dansgaard et al., 1993). Based on this
record, it seems plausible that the climate will fluctuate between glacial and
interglacial states during the period suggested for the performance assessment
calculations. Thus, the specified upper boundary, or the physical top boundary of
the modeled system, should be able to reflect these variations (especially in terms
of groundwater recharge).
(NAS Report pp. 77-78)
NAS also stated that it is impossible to know with any certainty when transitions to glacial
climate would occur, but noted that it surely will occur over the next 1 million years. (NAS
Report p. 91) The committee suggested that a doubling of the effective wetness may be
sufficient for a scenario that encompasses climate change over the compliance period of 1
million years (discussed in greater detail below). We agree with that premise, and also
believe that uncertainties about predicting the precise timing and magnitude of future
climatic fluctuations cannot be significantly reduced by additional research into past
climatic cycles or modeling of current climate. Therefore, we believe that the stylized
scenario NAS proposed is a reasonable indicator of repository performance out to 1 million
years.
In an effort to avoid confusion, we will first define some of the terms as we use them in this
section, and in the preamble to the final rule. These terms are used in the broad context of
the discussion on climate change and how it may affect the disposal system, but it should
be remembered that our rule language specifically states that the climate change analysis is
limited to the effects of increased water flow through the repository (incidental of its path
to the repository, which is left to the discretion of the NRC to determine) as a result of
climate change. Using the definitions below, we have attempted to trace liquid movement
from the atmosphere to the repository.
•	Precipitation means any form of water particles, such as frozen water in snow or ice
crystals, or liquid water in raindrops or drizzle, that fall from clouds in the
atmosphere and reaches the earth's surface.
•	Infiltration means the process of water entering the soil at the ground surface and
the ensuing movement downward when the water input at the soil surface is
adequate. Infiltration becomes percolation when water has moved below the depth
at which it can be removed (to return to the atmosphere) by evaporation or
evapotranspiration. Percolation is also referred to by the NRC as deep percolation
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(70 FR 53315), and is defined by NRC as the amount of water that is available to
reach the repository horizon. We use percolation in the same context as NAS used
the term effective wetness which they defined as the ratio of precipitation to
evapotranspiration. (NAS Report p. 91) NAS was concerned about quantifying the
flux of water through the unsaturated zone, which could affect rates of radionuclide
release from waste forms, and transport to the water table.
• Seepage means the inflow of ground water moving in fractures or pore spaces of
permeable rock to an open space in the rock, such as a drift. Specifically, the
amount of percolation flux that enters the drift in a given time period. In this case,
seepage refers to the water that flows into the repository, and contributes to the
release and transport of radionuclides out of the repository.
Commenters 0105 and 0226 remarked that we had failed to recognize the true ambiguity of
climate change. We disagree. We indeed recognized the ambiguous and unpredictable
nature of climate change, which is why we proposed to eliminate as much ambiguity as
possible by using the NAS suggested stylized scenario focusing upon increased seepage
into the repository. We were also concerned about the possibility of over-speculation of
climate change (as evidenced by the comments we received) over such extremely long time
periods, possibly out to the next 1 million years. The NAS also recognized this fact in its
report, stating "Although the typical nature of past climate changes is well known, it is
obviously impossible to predict in detail either the nature or the timing of future climate
change. This fact adds to the uncertainty of the model predictions." (NAS Report p. 77)
As we stated in the preamble to the proposal (70 FR 49058), we agree with the NAS
direction to us and stated that it is not useful to have unconstrained speculation on future
climate during the period of geologic stability, because (as we saw in the comments) it is
possible to assume any number of scenarios of climate over this large amount of time, and
there is very little evidence available to accept or refute most of them. Because it is not
possible to predict every situation that could occur over such a long time, we felt that the
best course was to construct a climate scenario that results in reasonable rates of water
flow into the repository , and allow this scenario to run throughout the period of geologic
stability.
To reiterate, we are more concerned about the overall net increases in water flow (seepage)
through the repository, and how that may contribute to increased release and transport at
the repository. As we stated, we do not believe that it is important to know or predict, with
certainty, precisely when climate states with peak precipitation occur during the
performance period, because there are too many permutations and uncertainties in trying to
project a future set of climate conditions.
For example, Commenter 0298 provided information that the change from the current
interglacial period to a cooler, wetter glacial climate may be delayed up to 500,000 years
because of anthropogenic insertion of carbon dioxide into the atmosphere. Commenters
0312 and 0314 argued that connections of climate with the El Nino Southern Oscillation
(ENSO) cycles, solar variability, increased atmospheric carbon dioxide, and ocean-
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atmosphere interactions are unclear. Factors influencing the timing of climate cycles, the
role and mechanisms of global oceanic circulation, global effects of land use and land
surface alterations, and the role of biological processes are yet to be clearly defined in
association with climate change. Also, nonlinear responses to small increases in
precipitation present great challenges in predicting the behavior of hydrologic systems over
long time periods. We agree with the commenters that the uncertainties are too great to
make specific, precise predictions about future climate states.
We also agree with NAS, that for extremely long time periods, major changes in the global
climate, for example a transition to a glacial climate, could affect ground-water movement.
NAS states "Change to a cooler, wetter climate at Yucca Mountain would likely result in
greater fluxes of water through the unsaturated zone." (NAS Report pp. 91-92) NAS
observed that a doubling of the effective wetness (the ratio of precipitation to effective
evapotranspiration) could cause a significant increase in recharge. (NAS Report p. 91)
This could affect the rates of radionuclide release from the waste and transport to the water
table, although the location of the repository in the subsurface would provide a time lag for
climate change effects. NAS states, "The time required for unsaturated zone flux changes
to propagate down to the repository and then to the water table is probably in the range of
hundreds to thousands of years. The time required for saturated flow-system responses is
probably even longer. For this reason, climate changes on the time scale of hundreds of
years would probably have little if any effect on repository performance, and the effects of
climate changes on the deep hydrogeology can be assessed over much longer time scales."
(NAS Report p. 92)
We proposed to explicitly require that DOE assume water flow into the repository will
increase as a result of climate change. We left it to NRC as the licensing authority to
specify the values to be used to represent climate change in estimating water flow.
However, we expect that a doubling of today's average seepage beginning at 10,000 years
and continuing through the period of geologic stability would provide a reasonable
scenario, given NAS's statements regarding potential effects on recharge. (NAS Report pp.
91-92) NRC could also use the range of projected precipitation values for different climate
states and specify a reasonable long-term average precipitation based on the duration of
each climate state over the period of geologic stability. We believe that either approach
will allow for a reasonable estimate of how water will impact the site without subjecting
the assessments to speculative assumptions that may well be irresolvable, while providing a
reasonable indicator of disposal system compliance. NRC might choose to express the
ground-water flow effects directly as infiltration, percolation or seepage rates or other
representative parameters, avoiding the necessity of translating precipitation and other
climate-related parameters
There are too many uncertainties in trying to project a future set of climate conditions, and
it is difficult to place specific times on when discrete pulses of precipitation should be
injected into the modeling. (NAS Report p. 77) Instead, we believe that it is reasonable to
assume an average increase in seepage into the repository over the entire time from 10,000
years through the period of geologic stability to 1 million years, and to model those
consequences. An increase in average seepage throughout the period of geologic stability
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is a more reasonable approach because it assumes a constant source of water eventually
reaching the repository. This scenario need not be dominated by highs or lows in
precipitation over the time period and does not require speculation about the exact timing
or transient effects of shifts in climate. Rather, setting a constant value somewhat higher
than today's average annual rainfall (large enough to account for the increase in seepage
into the repository) and extending it out through the period of geologic stability would
account for the greater potential for available fluids at the time of the failure of the waste
packages. We believe that this approach provides a reasonable test of the repository
conditions throughout the period of geologic stability, and will give a more conservative
estimate of potential fluid flow, as well as potential for migration of radionuclides out of
the repository.
Our line of argument in the preamble was to have DOE determine how the disposal system
responds to the effects of a permanent increase in water flow through the repository as a
result of climate change. We believe that the idea of increased water flow was lost on
many commenters, who stated that they were opposed to our use of an unchanged seepage
rate, the connotation being that the climate parameters would remain the same as we see
today. We did not propose to use the current climate state at Yucca Mountain, nor did we
propose modeling with less water flow into the repository. We attempted to follow the
direction that NAS gave us. This could affect the rates of radionuclide release from the
waste and transport to the water table, although the location of the repository in the
subsurface would provide a time lag for climate change effects. For this reason we require
a permanent increase of water flow through the repository, in contrast to using
unpredictable cycles of precipitation/infiltration that, at low points, would be similar to the
infiltration found in the area today, in order to maximize the potential for effects to be seen.
Commenter 0209 stated that future climate at Yucca Mountain is important because it
strongly influences the rate at which waste containers and other metal barriers corrode. We
agree in principle with the comment. The availability of water to contact the waste
packages is an important initiator for corrosion processes. However, we also recognize that
corrosion is also correlated with respect to temperature in the repository. We have
considered the effects of climate by requiring an increase in the amount of water flow into
the repository. This will allow a constant, steady migration of water into the repository.
This in turn will allow water to constantly be available, and should produce a conservative,
yet reasonable rate of degradation for the engineered barriers in the repository.
Commenter 0258 suggested that we should not equate climate situations in Europe with the
Yucca Mountain area, because the two situations will be different. Certain European
facilities may be covered with glaciers, while Yucca Mountain will only see increased
precipitation. We agree, and our proposed future climate requirements were in agreement
with the commenter; namely an increase in water flow into the repository. We are more
concerned with how the repository system responds to a larger influx of moisture, and we
have resolved this by recommending that the effective moisture be increased. We believe
that this represents a cautious, yet reasonable approach in attempting to project disposal
system response to climate change.
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Commenters 0174 and 0302 asked why we did not modify the behavior and characteristics
of future populations, even though we acknowledged that some circumstances may be
different with increased infiltration (e.g., higher release rate of radionuclides from the
repository into the ground water). We followed the advice of NAS regarding the possible
changes in characteristics of society in the future. NAS described several changes that
climate change could impart on the disposal system. One of the changes might be a shift
in the distribution and activities of human populations. (NAS Report p. 92) A cooler,
wetter climate may provide a more hospitable environment, increasing the population, and
(some have argued) possibly changing the parameters we have outlined for future
societies. NAS also noted, "there is no simple relation between future climatic conditions
and future population." (NAS Report p. 92) We acknowledged this situation in the
preamble to the proposal (70 FR 49059), and chose not to modify any conditions for future
populations, because we continue to believe that the proposed lifestyle we chose is
conservative, but similar to that of most people living in Amargosa Valley today.
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Section 9 Intergenerational Equity
Issue A: General comments regarding intergenerational equity
1.	The proposal assumes it is ethically permissible to expose future generations to radiation
levels far higher than would be tolerated today. (Comment 0103-4)
2.	The standard will burden future generations of Nevadans with significantly higher
radiation exposure than ourselves. (Comments 0126-1 and 0127-1)
3.	The EPA is dismissing the need for generational equity and is instead claiming that
future generations should face some of the highest radiations doses in the world.
(Comments 0130-1 and 0195-5)
4.	The attempt to bifurcate this radiation standard throws out all attempts at generational
equity and puts future generations at tremendous risk. (Comment 0132-1)
5.	The increased dose limit after 10,000 years is a complete violation of principles of inter-
generational equity, as well as public health and environmental protection. (Comment
0133-2, 0135-2, 0137-2, 0141-2, 0146-2, 0147-2, 0148-2, 0159-2, and 0163-2)
6.	You're proposing to allow very high levels of radiation after 10,000 years. I don't think
deciding that after 10,000 years we don't need to worry about radiation on future
generations is a good idea. I don't want them exposed to high levels of radiation any more
than I do my grandchildren. (Comment 0136-1)
7.	It is irresponsible fiscally, environmentally, and inter-generationally. The land and its
surroundings would be rendered unfit for habitation for a period in excess of the number of
years homo sapiens have walked the earth. (Comment 0142-2)
8.	It is unethical to expose future generations to higher levels of radiation than current
generations. Yet, EPA throws this fundamental principle out by applying a standard that is
70 times weaker for future generations. EPA is proposing to allow an action that will kill
and harm people for hundreds of thousands of years, people who had no say in the decision
nor received any benefit from it. (Comments 0145-4, 0293-7, and 0302-9)
9.	People are our prime natural resource. I find transference of exposure to our toxic
garbage to future generations to be ethically repulsive! Do you remember the courageous
citizens of West Valley? They decided prior to the partial clean-up that they wanted to have
now the maximum allowable exposures, rather than pass these exposures on to future
generations. You are out of touch with the spirit of the American people.
(Comments 0151-1 and 0169-1)
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10.	EPA has correctly noted that the reasonable goal is to assure that current activities
would not be expected to create catastrophic or irreversible harm. This is a reasonable and
appropriate goal that we should aspire to for all human activities, but do not. Certainly, the
350 mrem per year limit EPA will apply to Yucca Mountain, which is in fact a stricter limit
than we now permit for indoor radon, falls well below this threshold. (Comment 0174-4)
11.	This is a complete violation of principles of intergenerational equity, as well as public
health and environmental protection. (Comment 0175 -2, 0177-2)
12.	What will we tell future generations when they ask why a huge portion of the
southwestern United States is nearly uninhabitable? (Comment 0199-2)
13.	Unfortunately, contrary to the unequivocal directions provided by the D.C. Circuit
Court of Appeals, the current proposed radiation standard fails to adequately protect health
and safety. Although proponents of the new standard argue that this rule actually provides
health and safety guarantees for an unprecedented one million years, the standard, in
reality, in fact, permits future generations of Nevadans to be intentionally subjected to
radiation levels prohibited everywhere, both nationally and internationally. (Comment
0209.6-2)
14.	Rather than promulgating a revised radiation protection standard more stringent than
the previous standard in the interest of public health and safety, EPA actually relaxes the
standard. Even though EPA previously determined that citizens should be exposed to no
more than 15 millirems per year, the new proposed standard would permit exposures of
between 350 and 1,050 millirems per year, depending on whether median or mean
exposures are considered. This relaxation of protection for citizens living close to the
proposed repository amounts to the least stringent radiation protection standard in the
world. (Comment 0209.6-3)
15.	On behalf of the Nevada Department of Justice, I respectfully urge EPA to rescind its
proposed rule. In the interest of protecting public health and safety, it is imperative that
EPA design a standard truly capable of protecting present and future generations of
Nevadans from unacceptable radiation levels when the radiation risks are at their peak.
(Comment 0209.6-8)
16.	If adopted, the proposed Yucca Mountain standard will permit countless generations of
Nevadans to be intentionally exposed to levels of radiation that would never be tolerated
anywhere else, either in the United States or internationally. (Comment 0209.7-3)
17.	DOE tells the nation not to worry, these levels of radiation won't be experienced for
200,000, 300,000 years. But the proposed standard will be set today to accommodate that
level of radiation. Even if it were moral to argue that it's okay to delay the risk to unborn
generations of the future, the legal allowance will be in place to accept and institutionalize
that level of risk today. And it is certainly not moral to delay the risk.
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Under the proposed rule, these doses would be permitted to occur generation after
generation for hundreds of generations. It's hard to conceive of a proposed environmental
regulation or action that raises such serious questions of generational immorality.
EPA is proposing to commit an action that will kill people for hundreds of
thousands of years, people who have no say in the decision nor received any support or
benefit from it. They bear only the cost, a huge human cost. (Comment 0209.12-4)
18.	But all of the people you quote say things like target, qualitative, benchmark —
remember all of those kinds of — vision. There's all of those words you used to say that
when we go out beyond, we've got to take a somewhat different logic. Okay, do it.
But just because you do that means that you can say any standard is the most morally — the
most biologically recommended, but we don't know how to ascertain it. In other words, you
can recommend beyond, why recommend 350 when you can recommend 15? (Comment
0209.16-2)
19.	So when you guys look at these things, you need to really think about what you're
doing because I have to look after generations that come behind me. I don't look at things
for myself. I'm here. I'll be gone in a few years, but there's generations that are coming
behind me that I have to look for. I have to protect. And you people need to do the same
thing. The government needs to think about what they're doing. And they really need to
protect the future generations because I hate to see my people be obliterated from this
Earth. And if that happens that is not something that we made. It's something that non-
Indians have done to us. (Comment 0209.17-3)
20.	Given the exceedingly poor record of radioactive contamination management at other
sites since World War II, the message is clear that the federal government and the U.S.
Congress considers the Southwestern U.S. and Northwestern Mexico to be expendable. The
irreversible effects of the contamination from 177,000 tons of high-level toxicity or lethal
radioactive material won't be felt for a few generations, so current politicians feel safe from
being held accountable during their own lifetime. As long as their present crop of local
voters aren't freezing in the dark or at immediate risk of deadly radioactive contamination
themselves, what do they care for the future residents of Nevada, Arizona, California and
Mexico, or for the Pacific Ocean? The radioactive contamination from Yucca Mountain
cannot be permanently contained, and we all know it. There is no manmade structure that
has ever stood as long as the half-life of Plutonium-239. Yucca Mountain will eventually
render an enormous area of this country permanently unfit for habitation. So the message is
simple: Millions of Southwesterners and our future generations are expendable. (Comment
0211.3-3)
21.	I'm here today to show you who you will be hurting. It is not your problem, and it is not
his problem, but it is our problem. It is my children and my children's children who will be
affected by this inhumane radiation standard. (Comment 0211.4-1)
22.	Your disregard for future generations is inexcusable and irresponsible. You must go
back and set the standards to truly protect us. (Comment 0213-1)
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23.	Mountain is in the cost of a system that is more expensive than necessary to provide
adequate protection. In the case of the Yucca Mountain repository, the value to society is so
high that the cost of the design is not a substantial issue. Another impact.. is the imposition
of an extraordinarily difficult burden of proof on the licensee and an associated delay in
opening the repository. Delay has two effects. First, it increases the hazard from radioactive
waste that could be more safely stored in a geologic repository. Second, the unavailability
of a licensed repository is the principal barrier to the expansion of nuclear power. A major
expansion of nuclear power may represent the only feasible approach to transition from a
fossil-fuel based economy to a sustainable energy economy that would not lead to a
substantial reduction in our standard of living. The longer that transition is delayed, the
greater the financial impact on world economies and the global environmental impact from
the emission of greenhouse gases. (Comment 0215-2)
24.	Despite the new amendments, I do not believe there are sufficient safeguards in place to
protect future generations. (Comment 0218-1)
25.	The plan inexcusably calls for the relaxing of the radiation standards over time, putting
future generations and the fragile web of life at risk. I believe that a weak or minimal
principle of justice is not an acceptable principle to apply to any generation, now or in the
future. To discount the value of future generations and knowingly allow increased
exposure to radiation and potentially increased cancer rates is wrong, plain and simple.
(Comment 0221-1)
26.	EPA's failure of explanation stands in sharp contrast to its prior Yucca rule, in which
EPA clearly articulated the "fundamental principle of intergenerational equity" that "we
should not knowingly impose burdens on future generations we ourselves are not willing to
assume." 66 FR 32107. EPA does not explain whether it is abandoning this "fundamental
principle" now, or how its proposed rule, which quite clearly does impose additional
burdens on future generations, could possibly be reconciled with this "fundamental
principle." (Comment 0226-61)
27.	EPA's intergenerational equity rationale, to the extent that it exists, fails for an
important additional reason: EPA has never explained how a lax second-tier standard
benefits anyone. While EPA's entire theory appears to be that providing future generations
with the same protection we provide ourselves today would impose burdens upon present
generations, EPA has not stated what those burdens are. Indeed, it has identified no
possible trade-off that will result in any present harm if current levels of acceptable risk are
sustained after 10,000 years. If EPA is implicitly suggesting that the benefit to this
generation from the lax future standard is the present success of Yucca Mountain, it strays
into impermissible territory, for EPA has no authority to pre-determine that the Yucca
Mountain repository should be built regardless of health and safety threats. With the
NWPA and EnPA, Congress gave EPA one duty—to set the health-based radiation
standard for Yucca. It did not call upon EPA to evaluate whether the success of the nation's
repository program at Yucca today can justify a weaker standard of care for future
generations. EnPA section 801(a) (1) requires EPA to promulgate a "public health and
safety standard for protection of the public from releases [from Yucca]." Section 801(a) (2)
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refers to this standard as "health-based." A "public health and safety" or "health based"
standard must be based on a consideration of what is an acceptable level of risk; it may not
be based on economic costs or a balancing of costs and benefits. National Cottonseed
Products Ass'n v. Brock, 825 F.2d 482 (D.C. Cir. 1987) (citing American Textile
Manufacturers Ins't v. Donovan, 452 U.S. 490 (1981)); NRDC v. EPA, 824 F.2d 1146
(D.C. Cir. 1987); Union of Concerned Scientists v. NRC, 824 F.2d 108 (D.C. Cir. 1987).
Moreover, Nevada disputes whether Yucca Mountain would actually provide any benefit to
present generations. As Nevada has pointed out in detailed past comments, both the site
itself and, potentially more importantly, the massive project of transporting 70,000 tons of
nuclear waste across the country to the site pose enormous risks to present generations. See
Nevada, Comments on Department of Energy's Draft EIS. Similarly, a lax second-tier
standard provides significantly reduced protection to generations living within the 10,000-
year period. If the repository is licensed on the assumption that peak dose will occur after
10,000 years, and that assumption proves wrong, the first-tier standard will provide no
protection to the people who bear the brunt of the repository's impacts. Instead, those
generations, whom EPA has never suggested should receive the same minimal protection it
would accord to generations in the post- 10,000-year period, would be put at greater risk by
EPA's decision to rationalize a lax second-tier standard on the theory that later harms are
somehow more permissible. (Comment 0226-67)
28.	Permanent disposal of nuclear waste at Yucca Mountain is not a matter of balancing
risks to near-term generations against risks to far-future generations. Designing disposal
systems that would minimize harm to far future generations will also minimize the risks to
ourselves and our descendents over the next 10,000 years. The double standard proposed
for Yucca Mountain constitutes an admission that we do not yet know how to do this.
(Comment 0267-8)
29.	The proposed 40 CFR 197 provides a level of protection for the first 10,000 years after
the repository is closed, and less for those people after 10,000 years. In fact, the all
pathway standard is weakened by a factor of approximately 24, and the groundwater
standard is eliminated. Why should people living after 10,000 years be afforded less
protection? This is a blatant disregard to future generations and an irresponsible policy.
The 15 mrem/yr dose limit should be imposed through the period of peak risk, which is
more like 300,000 years (according to DOE's calculations), and the Safe Drinking Water
Standard should also extend through this period. (Comments 0268-1, 0289-2, and 0328-1)
30.	There is no justification for EPA using a 350 millirem standard at Yucca Mountain for
the time period after 10,000 years. We strongly beleive that we must plan now to protect all
our future descendants as well as we want to be protected today. (Comment 0274-1)
31.	EPA's proposed regualtions should NOT be adopted and are contrary to both law and
policy. The proposed standards fail to protect future generations and instead DUMP the
legacy of todays idiocy onto the citizens of tomorrow. EPA proposes to provide the DUMP
the benefit of the doubt that it is safe unless others prove it harmful EPA does this by
biasing the analysis based oin uncertainty in favor of releases rather than in toward
protection of individuals and the environment. This is both unconsionable and illegal. EPA
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should instead adopt a standard that is unifrom through time as propsed by Nevada, that
includes groundwater protection, that presumes loss of institutional control, that presumes
unrestricted use of all land save the repository itself. (Comment 0275-2)
32.	It should be pointed out that these huge doses proposed would not be for a single point
in time but would likely extends for hundreds of generations. People would be getting
doses that would result in something on the order of 1 out of every 36 of them, or worse,
getting cancer, from wastes produced millennia before them, based on decisions about
which they had no say. This would be a form of intergenerational immorality on a scale not
seen before in human history. (Comment 0296-5)
33.	Furthermore, [350 mrem/yr] is not a dose that occurs for a moment and then recedes to
far lower levels. Under the EPA proposed rule, these doses would be permitted to occur
generation after generation, for hundreds and thousands of generations. For EPA to
recommend such high levels of radiation exposure to generations in the distant future is a
complete reversal of progress in preventing human exposure to ionizing radiation.
(Comment 0301-7)
34.	EPA's proposal for a two-tiered radiation protection standard and two different
methods for assessing regulatory compliance is not only scientifically questionable, it is
also unethical and a gross violation of current EPA regulations (and internationally
accepted public health norms) that guarantee all individuals an equal protection against all
radiation exposure above the legal limit. Rather than providing better protection for future
generations, the new EPA rule sanctions a 2,300 percent higher exposure limit for
individuals living in the period beyond 10,000 years than what is permitted for individuals
in the first 10,000 years. Future generations, who had no part in creating the deadly nuclear
waste, are permitted to be poisoned without their consent under the proposed EPA rules.
(Comment 0301-8)
35.	Intergenerational equity has been the foundation of U.S. and international public health
and safety laws. Yet, in its draft rule, EPA throws this fundamental principle out by
applying a standard that is more than 23 times weaker for hundreds of future generations.
(Comment 0302-7)
36.	According to science ethicist Dr. Kristin Shrader-Frechette in her recent article in
Science and Engineering Ethics, "E.P.A.'s double radiation standards for different
generations... suggest that we merit more protection than our descendants. Yet we, not they,
profit from nuclear power plants that produce the radioactive waste." (Comment 0302-10)
37.	Do not assume that future generations will develop coping mechanisms to deal with
liabilities we have yet to find a solution for, such as the disposal of nuclear power reactor
waste. The EPA and other agencies are now, routinely, employing long-term "Institutional
Control" regulatory provisions to pass on massive liabilities to future generations. In the
case of DOE's nuclear explosives testing grounds, at the Nevada Test Site (NTS), one
remediation option was estimated to cost $7.29 trillion.* Due to economic and other
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impracticalities the Institutional Control option was chosen instead of actual cleanup.
(Comment 0309-5)
38.	On page 49027, column 3, EPA points to "site characterization studies, laboratory
testing, and expert judgment" as the analytical basis for the range of expected parameter
values. But EPA must keep in mind that the falsification of data, the use of uncalibrated
instruments, as well as documented corruption amongst the so-called "experts" on the
Yucca Mountain Project has thrown Yucca's scientific and technical bases into extreme
doubt. (Comment 0324-25)
39.	We who are alive today have a species responsibility toward those who follow us, to
provide protection from the residues of our radioactive waste-generating practices. EPA
must advise NRC to require DOE to do far better at designing and carrying out high level
waste isolation, and of assuring long-term isolation of the high-level wastes which NRC
and the DOE have heedlessly allowed the U.S. military and commercial nuclear industries
to produce. (Comment 0331-4)
40.	EPA's proposed radiation standard is the least protective radiation standard in the world
and is based on an assumption that it is permissible to expose future generations to
radiation levels far higher than what we would tolerate today. (Comment 0341-10)
41.	The EPA is endangering future generations. I pray that you will make better decisions.
(Comment 0343-3)
42.1 object to your recent issuing of standards for radiation protection for the Yucca
Mountain Project in Nevada. Please consider the well-being of our future generations.
(Comment 0346-1)
43.	[T]he 350 mrem/yr proposed by EPA represents an annual individual risk within the
range of annual individual risks associated with other EPA and NRC regulations that were
identified in the Committee report (Table 2.4 on page 50) as starting points for discussions
of risks. These risks range from greater than 10-4 to less than 10-6 and represent
approximate dose levels ranging from a few millirem to nearly a rem. It should be noted
that none of these other regulations apply for such a long period of time, so there is no
directly comparable precedent for how to apply any concept of intergenerational equity at
the time of peak dose. (Comment 0352-23)
44.	The attempt to bifurcate the radiation standard throws out all attempts at generational
equity and puts future generations at tremendous risk. (Comment 0354-2)
45.	The proposal would protect people for the first 10,000 years to currently applied
standards of protection, but would then doom future generations after that time to a 1 in 36
cancer rate (or even worse, up to a 100% cancer rate, due to EPA mathematical
manipulation), and a 1 in 72 fatal cancer rate (or even worse). Such proposed cancer rates
and fatal cancer rates are horrifying, and EPA must withdraw such an unacceptable
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proposal. This is a complete violation of principles of inter-generational equity, as well as
public health and environmental protection. (Comment 0355-1)
46. The point regarding future generations is here we are saying that we have standards for
us for 25 millirem today from a single nuclear facility. And we're saying we're going to get
the benefits and we're going to protect ourselves more than we're going to protect future
generations who are going to get none of the benefits. (Comment 0368.3-5)
Response to Issue A:
We received extensive comment on our proposal from the perspective of its potential
impact on far-future generations as compared to the current or next few generations.
Commenters on this point questioned our reasoning behind proposing a higher dose
standard for the far future, and disagreed with our interpretation of literature on the subject.
Ultimately, most commenters expressed the view that there is no justification for the level
of protection to be different from today's level, whether it is 10,000 or 1 million years (or
even longer into the future).
We first note that the NAS did not make a specific finding or recommendation with regard
to the concept of intergenerational equity. As discussed below, the NAS spoke in general
terms to this concept, but it did not make a recommendation that the Agency is obligated to
be consistent with. EPA remains committed to the principle of intergenerational equity,
which holds (in part) that the risks from a current action should not be greater to future
generations than would be acceptable today. A strict reading of this principle initially
would lead to the conclusion that the same level of protection must apply at all times, or for
as long as the action presents risks. However, we believe that peak dose limits over
extremely long times should be viewed as qualitatively different from limits applied at
earlier times; in other words, the basis for judgment at different times is not the same. We
believe the peak dose standard we are establishing in our final rule appropriately considers
this differing basis for judgment and provides the necessary protections for future
generations. We are not establishing the proposed 350 mrem/yr level as our final peak
dose standard; instead, we are establishing 1 mSv/yr (100 mrem/yr) as the public health and
safety standard to apply for the period beyond 10,000 years and up to 1 million years. As
discussed in the preamble to the final amendments, the dose level of 100 mrem/yr is well-
established as protective of public health, and as such represents a robust standard for
public health protection in the extreme far future. International organizations such as
ICRP, IAEA, and NEA recommend its use as an overall public dose limit in planning for
situations where exposures may be reasonably expected to occur. Domestically, both NRC
and DOE incorporate the 100 mrem/yr level into their systems of regulation (10 CFR
20.1301 and DOE Order 5400.5, respectively), and NCRP also endorses the ICRP system
of protection (NCRP Report 116, "Limitation of Exposure to Ionizing Radiation," Docket
No. EPA-HQ-OAR-2005-0083-0407).
In particular, we have tried to understand how the concept of intergenerational equity is
viewed when applied to periods up to 1 million years, because only in the context of
radioactive waste disposal has there been serious consideration of such time frames. For
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example, does the idea of "risks no greater than would be acceptable today" take on a
different meaning over periods during which human evolutionary change may occur, and
the state of society and technology develop in ways not reasonably foreseeable today?
Many commenters expressed the view that it does not. However, as we discussed in our
proposal, a number of regulatory and scientific bodies suggest that it may be appropriate to
relate longer-term standards to background radiation levels, which strictly speaking would
be "greater than would be acceptable today" from a waste management practice, but are not
routinely considered as a major risk factor in collective and individual decision-making.
The concept of intergenerational equity is of sufficient importance to underlie two of the
nine fundamental radioactive waste management safety principles endorsed by IAEA ("The
Principles of Radioactive Waste Management," Safety Series 111-F, 1995, in particular
Principles 4 and 5, respectively, Docket No. EPA-HQ-OAR-2005-0083-0053, which relate
to protection of future generations and burdens on future generations, respectively) and has
been incorporated into the Joint Convention on the Safety of Spent Fuel Management and
the Safety of Radioactive Waste Management (an international agreement ratified by more
than 30 countries, including the U.S., Docket No. EPA-HQ-OAR-2005-0083-0393). We
also considered in our proposal documents prepared by the National Academy of Public
Administration (NAPA) and Swedish National Council for Nuclear Waste (KASAM)
(Docket Nos. EPA-HQ-OAR-2005-0083-0077 and EPA-HQ-OAR-2005-0083-0197,
respectively). NAPA is a Congressionally-chartered organization whose purpose is to
provide assistance to government in assessing and effectively addressing issues of
governance, including future implications of contemplated actions. KASAM was created
by the Swedish government in 1985 to provide an independent review of issues related to
nuclear waste. The IAEA principles are discussed in Issue B of this section, and the NAPA
and KASAM documents are discussed in Issue C.
Commenter 0209.16 accuses us of being "disingenuous" by claiming there is no consensus
regarding obligations to future generations. The commenter has misunderstood our
statements. We do not question whether there is an obligation to future generations, but we
believe there is no consensus regarding the nature of that obligation, for how long it
applies, whether it changes over time, or how it can be discharged.10 Regarding
radioactive waste management and geologic disposal, there is general agreement that
assurances can be provided that the protections offered will be similar to those acceptable
today for periods approximating 10,000 years, which in itself is a very long time
(exceeding as it does the entire span of recorded human history). We reached such a
judgment in establishing the 15 mrem/yr standard in 40 CFR part 191 (and again in our
2001 rulemaking), based on our conclusions that the capabilities of disposal and modeling
technology were sufficient to allow implementation with reasonable expectation for 10,000
10 NEA reaches similar conclusions: "The design and implementation of a repository involves balancing of
risks and responsibilities between generations. The obligations of the present generation toward the future are
complex, involving not only issues of safety and protection but also of freedom of choice and of the
accompanying burden of responsibility, and of the need to transfer knowledge and resources. Our capacity to
deliver these obligations diminishes with distance in time, which complicates the setting of criteria to be used
today in order to demonstrate that obligations to the future will be met." ("Regulating the Long-Term Safety
of Geological Disposal: Towards a Common Understanding of the Main Objectives and Bases of Safety
Criteria," NEA-6182, 2007, p. 25)
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years (58 FR 66401, December 20, 1993; 66 FR 32097-32098, June 13, 2001). However,
as one considers times in the hundreds of thousands of years and beyond, can similar
assurances be offered when, as we believe, the underlying bases for those assurances have
fundamentally changed? What form can those assurances take (i.e., can we reasonably
make assurances regarding our ability to distinguish among and control incremental
radiation exposures over such long times)? Can they provide the same level of confidence?
We have selected a standard that is consistent with the public dose limit accepted
internationally and nationally, and therefore has a strong basis for protectiveness today.
We believe this is a reasonable level of commitment that will protect public health and
safety over such long times, given the complexities of the situation and what we see as our
responsibility to establish a level of compliance, not a soft target or reference level that
could be exceeded for unspecified reasons and by unspecified amounts.
A number of commenters cite the statements of the NAS committee regarding
intergenerational equity to support their position that a higher dose level for longer times is
contrary both to that principle and the NAS recommendation. We disagree, and have
discussed the second point in some detail in other sections of this document (see Section 2,
Issue C, for example). Regarding the question of intergenerational equity, we cited the
NAS discussion in our proposal (70 FR 49036). In citing NRC and IAEA sources, the
NAS wrote (NAS Report pp. 56-57, emphasis added):
A health-based risk standard could be specified to apply uniformly over time and
generations. Such an approach would be consistent with the principle of
intergenerational equity that requires that the risks to future generations be no
greater than the risks that would be accepted today. Whether to adopt this or some
other expression of the principle of intergenerational equity is a matter for social
judgment.
We generally agree with the NAS statement. A single dose standard applicable at all times
would typically be consistent with a close reading of the principle of intergenerational
equity. However, NAS clearly acknowledges that "some other" approach could also be
consistent with that principle. We believe it is reasonable to conclude that "some other"
approach must include situations where it may not be reasonable to apply the same dose
standard at all times because of the extremely long compliance period. We believe
establishing a peak dose standard for the Yucca Mountain disposal system is a situation in
which "some other expression of intergenerational equity" is more appropriate than is
applying a single dose standard of 15 mrem/yr throughout the compliance period. The
rulemaking process we are following is the accepted way for "social judgment" to be
incorporated into regulations.
NAS made no recommendation regarding the appropriate expression of intergenerational
equity, just as it made no recommendation regarding the level of the final peak compliance
standard. Rather, NAS acknowledged EPA's wide latitude to exercise its policy judgment.
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Further, as discussed in more detail in Section 2, Issue C of this document, Robert Fri, who
chaired the NAS committee, testified on March 1, 2006 before the Senate Environment and
Public Works Committee (Docket No. EPA-HQ-OAR-2005-0083-0380). Mr. Fri provided
his personal views on our proposal as it related to the NAS recommendation regarding
compliance at the time of peak dose. He expressed the opinion that extending the 15
mrem/yr standard to the time of peak dose, if it were to be judged against the RMEI, "runs
the risk of excessive conservatism," although this combination of dose limit and receptor
was acceptable at 10,000 years. He noted that one committee member had recommended
such an approach combining long time frames with a "deterministic" receptor, which was
rejected by the committee (see pp. 100-103 and Appendix D of the NAS Report for this
alternative view). The committee had recommended use of a probabilistic critical group,
which we believe would have led to lower projected doses than would the RMEI we
defined (see Section 2 of this document). Mr. Fri did not offer an opinion on the
consistency of our 350 mrem/yr proposal with the NAS recommendation; however, he
viewed it as intended to reduce "the risk of excessive conservatism." We believe his
testimony can reasonably be interpreted as suggesting that there are circumstances in which
applying 15 mrem/yr throughout the 1 million-year compliance period could result in a
standard directly contrary to the committee's overall goals, which emphasized the use of
"cautious, but reasonable" assumptions and care in the use of "pessimistic scenarios and
parameter values." (NAS Report pp. 100 and 79, respectively) In such a case, it must be
considered whether such a conclusion would have implications for the appropriate
expression of intergenerational equity.
In light of the NAS statements, we have also considered how to identify the appropriate
"expression of the principle of intergenerational equity." First, we have considered the
nature of the compliance demonstration that DOE is to provide. Over the extended time
frames established in our rulemaking, we believe there are significant uncertainties
affecting the ability to project doses and make meaningful distinctions among those
projections. We also recognize that the capability of the technology used to assess
compliance is a factor that has been considered in the setting of public health protection
standards (e.g., remediation technologies or contaminant detection limits). As a result, we
believe it is appropriate to consider potential exposures in the very far future in a broader
context of protectiveness. From these perspectives, the 100 mrem/yr level is comparable to
the range of risks represented by domestic and international regulations identified by NAS
for EPA to consider, "all of which are consistent with recommendations from authoritative
radiation protection bodies". (NAS Report p. 49 and Tables 2-3 and 2-4) The nominal
annual risk of fatal cancer associated with 100 mrem/yr, 5.75 x 10"5, is reasonable when the
significantly extended time frames under consideration, with the attendant uncertainties,
are taken into account.11 We have determined that the final peak dose limit is protective of
public health and safety and provides a reasonable test of the disposal system for the time
frames in question. See also Section 6 of this document for discussion of uncertainties.
11 The Agency concludes that it is not reasonable to apply its traditional risk-management policies, in which
the goal is to constrain lifetime excess cancer risk to between 10"4 and 10"6, when establishing a compliance
standard applicable for periods longer than 10,000 years and up to 1 million years. The Agency does not
believe it is reasonable to view projected doses of 100 mrem/yr in the extreme far future as comparable to
doses of 100 mrem/yr incurred today, or even projected to occur within 10,000 years.
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Commenter 0352 similarly notes that none of the regulatory precedents considered by NAS
in developing its "starting point" for the peak dose (risk) standard applied for periods
approaching 1 million years, so there is no basis for drawing comparisons or making
conclusions regarding fulfillment of principles of intergenerational equity. Nevertheless,
we find that our final standards represent a valid and appropriate expression of
intergenerational equity.
Commenter 0226 cites legal precedents in charging that our proposal violated the EnPA
direction to establish "public health and safety standards" by not including specific analysis
of public health impacts, and argues as well that erroneous assumptions regarding the
timing of the peak dose would put people at greater risk within the first 10,000 years. Our
final peak dose standard of 100 mrem/yr is consistent with the internationally and
nationally accepted public dose limit, and we conclude that the nominal annual risk of fatal
cancer from this dose is reasonable and comparable to the range of risks NAS suggested
EPA consider, particularly when applied for up to 1 million years. We have determined
that this standard will protect public health and safety for up to 1 million years, and have
reason to believe that the peak dose standard will also have the effect of constraining
projected doses below 15 mrem/yr for the first 10,000 years (see Section 6 of this
document). It is NRC's responsibility to evaluate DOE's technical case for compliance
with our standards. The legal aspects of the comment are addressed in Section 24, Issue F,
of this document.
Section 9 Intergenerational Equity
Issue B: EPA's standards violate IAEA principles of intergenerational equity
1. EPA's proposed rule is similarly suspect in light of the NWPA, which requires protection
for future generations. In the NWPA, Congress stated that "appropriate precautions must be
taken to ensure that such waste and spent fuel do not adversely affect the public health and
safety and the environment for this or future generations." NWPA § 111(a)(7). This
Congressional statement supports EPA's erstwhile "fundamental principle" that "we should
not knowingly impose burdens on future generations that we ourselves are not willing to
assume." 66 FR 32107. But it is irreconcilable with EPA's current proposal to subject future
generations to burdens that current generations have never deemed acceptable. Congress's
statement is similarly inconsistent with any implication that future generations need not be
accorded protection and ethical standing. EPA's proposed rule also violated the Joint
Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive
Waste Management, to which the United States has agreed. That convention provides that
contracting parties shall take appropriate steps to "strive to avoid actions that impose
reasonably predictable impacts on future generations greater than those permitted for the
current generation." Section 101 of the National Environmental Policy Act has similar
language in its declaration of a national environmental policy. The EPA rule reflects no
such effort. It instead is predicated on an unlawful repudiation of this principle, for it would
purposefully "impose reasonably predictable impacts on future generations greater than
those permitted for the current generation." (Comment 0226-62)
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2.	The EPA rule is also contrary to one of the key IAEA "Principles of Radioactive Waste
Management" (IAEA 1995), agreed to by the United States, that "radioactive waste shall be
managed in such a way that predicted impacts on the health of future generations will not
be greater than relevant levels of impact that are acceptable today." EPA offers no reason
why the United States should change its policy now with respect to Yucca and Nevadans.
Nor does it have the authority to set or change U.S. policy in this regard; its sole duty here
was to set a health-based standard that would protect this and future generations.
(Comment 0226-63)
3.	Relaxation of radiation protection standards for future generations who will not benefit
from nuclear power plants that produced the waste is contrary to basic ethics, cost-benefit
analysis principles, and internationally accepted radiation protection guidelines, including
for radioactive waste. These widely accepted guidelines include those by the International
Atomic Energy Agency and the International Commission on Radiological Protection and
radiation protection authorities in other countries. This has been recognized by scientific
bodies, including the National Academy and in the past by the EPA. (Comment 0314.1-1)
4.	EPA does not explain how this two-tiered standard is consistent with this widely
accepted "intergenerational equity" principle, particularly since the 350-millirems-per-year
standard greatly exceeds the acceptable radiation dose limit (10 to 30 millirems per year)
described in the NAS report which is based upon a general consensus in the scientific
community for the exposure limit allocated to high-level waste disposal. The NAS 1995
report referred to the principle of "intergenerational equity", which states that the risks to
future generations should be no greater than the risks that would be accepted today. We
recommend that EPA adopt this principle of "intergenerational equity" by establishing a
radiation protection standard that applies uniformly over time and subsequent generations,
i.e., would not increase from 15 to 350 millirems per year after 10,000 years, as EPA
proposes in their revised standards. EPA in its prior 2001 standard explained the
"fundamental principle of intergenerational equity" by stating that "we should not
knowingly impose burdens on future generations we ourselves are not willing to assume.'
66 Fed. Reg. at 32107. EPA does not explain how the proposed rule, which imposes higher
risks on future generations by raising the limit from 15 millirem per year to 350 miilirems
per year, is consistent with this principle. (Comment 0326-1)
5.	The level of protection of 350 mrem/yr is consistent with the general principle of
intergenerational equity... [which] has two aspects. These aspects are that the current
generation should (1) strive to avoid actions that impose reasonably predictable impacts on
future generations greater than those acceptable today and (2) act in a manner that avoids
the imposition of undue burdens on future generations. The current generation must devise
and implement a safe and workable means of disposition of radioactive waste that does not
simply defer the problem to future descendants, or impose unacceptable risks on them.
Selecting a level that is toward the upper end of the risks that are considered acceptable
today is an appropriate way to ensure intergenerational equity by reducing the risk that the
inherent and almost unavoidable conservatisms in a repository performance assessment
might lead to rejection of a repository that would provide adequate protection to the public
today, or in the far distant future. At the extreme, it would be possible to select a level of
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protection so low that it would undercut the national policy of geologic disposal and thus
prevent the current generation from fulfilling its responsibilities to take care of the waste it
has generated. (Comment 0352-25)
6. Finally, but most importantly, this proposed standard is immoral. It has long been
resolved both in the United States and internationally that it is unethical to expose future
generations to much higher levels of radiation than current generations. EPA stated as
much in its final rule for its first radiation standard for Yucca Mountain. Yet EPA's
proposed rule blatantly tramples on the principle of intergenerational equity. Equal
protection under the law is a cherished American principle. EPA's proposal violates this
protecting certain generations to one standard but other generations to a much weaker
standard. (Comments 0368.13-5 and 0368.6-7)
Response to Issue B:
Several comments referred to principles of intergenerational equity as set forth by the
International Atomic Energy Agency (IAEA), cited by NAS in its discussion of
intergenerational equity. (NAS Report pp. 56-57) Many of the more general comments in
Issue A of this section expressed similar positions, but did not refer to the IAEA principles.
In 1994, the IAEA defined intergenerational equity in two of its principles of radioactive
waste management:12
Principle 4: Radioactive waste shall be managed in such a way as to assure that
predicted impacts on the health of future generations will not be greater than relevant levels
of impact that are acceptable today.
Principle 5: Radioactive waste shall be managed in such a way that will not impose
undue burdens on future generations.
In considering how to establish public health protection standards for periods up to 1
million years, these principles form the basis for judgments as to how well those standards
conform to the overall objectives of intergenerational equity.13 We will focus on Principle
4 (impacts on future generations), as the emphasis in Principle 5 (undue burdens) is to
encourage the current generation to take steps to manage the waste, rather than leave
decisions to succeeding generations, although there is recognition that succeeding
generations should have some degree of flexibility in carrying out the plans of the current
generation (to the extent that burdens may relate to environmental impacts, such as the
need to remediate ground-water contamination, they would essentially be addressed under
12	"The Principles of Radioactive Waste Management," Safety Series 111-F, 1995 (Docket No. EPA-HQ-
OAR-2005-0083-0053)
13	The Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste
Management (an international agreement ratified by more than 30 countries, including the U.S.) includes
similar statements in its General Safety Requirements: "(vi) strive to avoid actions that impose reasonably
predictable impacts on future generations greater than those permitted for the current generation"; and "(vii)
aim to avoid imposing undue burdens on future generations." (Chapter 3, Article 11) (Docket No. EPA-HQ-
OAR-2005-0083-0393)
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Principle 4).14 The current policy to pursue disposal would thus be consistent with the
intent of Principle 5. However, such considerations are outside the scope of our statutory
responsibility for this rulemaking. Our role is limited to the development of health and
safety standards for a specific course of action, geologic disposal at Yucca Mountain. We
are not making judgments regarding the appropriateness of geologic disposal as a waste
management policy in general, or the suitability of the Yucca Mountain site in particular.15
A strict reading of Principle 4 initially would lead to the conclusion that the same level of
protection must apply at all times, or for as long as the action presents risks. Many
commenters encouraged this interpretation. However, we have noted the typical practice
internationally, which is to establish a firm compliance standard for an initial period, then
to view dose projections as more qualitative indicators at longer times, without a firm
compliance requirement (see the preamble to the final amendments).16 Perhaps, though,
this is an accepted interpretation of Principle 4, because the initial compliance level is often
used as a reference or goal for the longer-term projections, suggesting that the intent is to
continue to use the initial compliance level as a guideline for decision-making.17 If so, we
must consider 1) whether an approach specifying a different level of protection as a
compliance standard for the far future can also be consistent with Principle 4 and 2) if so,
what role considerations of intergenerational equity play in determining that longer-term
level of protection.
Because IAEA has defined the basic obligation to future generations from radioactive
waste management, we are using it as the primary reference point forjudging consistency
with those obligations. A key question is the meaning of the term "predicted impacts" in
Principle 4. We have cited IAEA documents to the effect that projected doses for periods
14	"This principle is based on the ethical consideration that the generations that receive the benefit of a
practice should bear the responsibility to manage the waste. Limited actions, however, may be passed to
succeeding generations, for example, the continuation of institutional control, if needed, over a disposal
facility." (Paragraph 317); "The management of radioactive waste should, to the extent possible, not rely on
long term institutional arrangements or actions as a necessary safety feature, although future generations may
decide to utilize such arrangements, for example to monitor radioactive waste repositories or retrieve
radioactive waste after closure has been effected." (Paragraph 320)
15	Similarly, we have no basis to conclude that the near-term consequences of not licensing the Yucca
Mountain repository are so dire that the safety of future generations can be compromised, or that nuclear
power should or should not be pursued. The question of waste retrievability, which may require balancing
the need for complete containment and isolation of the waste with the need to allow future generations to
implement alternative policy decisions, also does not affect our disposal standards. The overall framework
supporting geologic disposal as the national policy was established by Congress, and it is the responsibility of
Congress to weigh the factors affecting the urgency or workability of that policy, and to identify alternative
methods for managing wastes, if necessary. Congress thus has the responsibility to ensure that future
generations are not overly burdened by current policies and actions, but are, in fact, provided the necessary
resources to conclude or improve on those actions (and then are able, in turn, to meet their obligations to the
future).
16	The UK is an exception to this practice, as it has established a risk "target" that applies throughout the life
of the facility. ("Disposal Facilities on Land for Low and Intermediate Level Wastes: Guidance on
Requirements for Authorisation")
17	In the French standard III.2.f, "Guidelines for Geologic Disposal," for the initial period, a level of 25
mrem/yr "determines the acceptability of the dose." At later times, when dose projections are supplemented
by more qualitative arguments for safety, it is considered a "reference level."
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longer than 10,000 years should increasingly be considered "illustrative" or "indicative"
and that the "aim of the assessment is not to predict the actual performance of the disposal
system."18 However, it may be argued that the cited documents are lower-level technical
guidance documents, and not reflective of the views of the IAEA as a whole. The most
recent IAEA publication of interest, however, is the 2006 Safety Requirements document
on "Geological Disposal of Radioactive Waste" (WS-R-4, Docket No. EPA-HQ-OAR-
2005-0383). Safety Requirements documents are the highest-level IAEA publications on
specific topics, and are consensus documents of Member States. As such, they can be
legitimately viewed as representing the positions of the IAEA and wholly consistent with
its principles of radioactive waste management, including Principle 4.
On the predictive capability of dose assessments, WS-R-4 states: "It is recognized that
radiation doses to individuals in the future can only be estimated and that the uncertainties
associated with these estimates will increase for times farther into the future. Nevertheless,
estimates of doses and risks for long time periods can be made and used as indicators for
comparison with the safety criteria."19 (Section A.3) This indicates that, while they may
not be viewed as "predictions," dose projections can provide useful information in relation
to the safety criteria for "long time periods."
However, "an indication that calculated doses could, in some unlikely circumstances,
exceed the dose constraint need not necessarily result in rejection of a safety case. In very
long timeframes, radioactive decay will reduce the hazard associated with the geological
disposal facility; however, uncertainties could become much larger and calculated doses
may exceed the dose constraint. Comparison of the doses with doses from naturally
occurring radionuclides may provide a useful indication of the significance of such
cases... Care has to be exercised in applying the criteria for periods beyond the time where
the uncertainties become so large that the criteria may no longer serve as a basis for
decision making." (Section A.7) This indicates that at some point comparison with the
safety criteria does not, and perhaps should not, establish a basis for judgments about
facility safety.
WS-R-4 does not specify "the time where uncertainties become so large." However, other
references in the document provide a reasonable basis for characterizing such terms as
"very long timeframes" and "long time periods." WS-R-4 makes the following specific
references to time periods associated with disposal (emphases added):
3.30 The containment of the radionuclides in the waste form and packaging over an
initial period of hundreds to thousands of years ensures that the majority of
18	"Safety Indicators in Different Time Frames for the Safety Assessment of Underground Radioactive Waste
Repositories," TECDOC-767, 1994, Docket No. EPA-HQ-OAR-2005-0083-0044; and "Regulatory Decision
Making in the Presence of Uncertainty in the Context of Long Lived Radioactive Wastes," TECDOC-975,
1997, Docket No. EPA-HQ-OAR-2005-0083-0045, respectively. We also note the NAS statement that "The
results of compliance analysis should not, however, be considered as accurate predictions of the expected
behavior of a geologic repository." (NAS Report p. 71)
19	The "safety criteria" include an overall dose limit of 1 mSv/yr (100 mrem/yr) and a source-specific
constraint (i.e., for a single disposal facility) of no more than 0.3 mSv/yr (30 mrem/yr). (Section 2.12)
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shorter lived radionuclides decay in situ (Requirements concerning
containment);
3.32 The geological disposal facility shall be sited in a geological formation and at
a depth that provide isolation of the waste from the biosphere and from
humans over the long term, for at least several thousand years, with account
taken of both the natural evolution of the geological disposal system and
events that could disturb the facility (Requirements for isolation of waste);
3.35 Over time periods of several thousand years or more, the migration of a
fraction of the longer lived and more mobile radionuclides from the waste in a
geological disposal facility may be inevitable (Requirements for isolation of
waste).
We believe it is reasonable to summarize the IAEA's position as follows:
•	For "at least" several thousand years ("the long term," which may perhaps extend to
10,000 years), the waste should be isolated from the biosphere and humans;
•	Releases of radionuclides are inevitable, perhaps beginning late in the initial "long-
term" period;
•	During this initial "long-term" period, the dose constraint should not be exceeded
except in "unlikely circumstances" (i.e., low-probability scenarios);
•	In "very long timeframes" (tens to hundreds of thousands of years), the dose
constraint may be exceeded in other than low-probability situations without causing
rejection of the safety case;
•	At these times, the safety criteria applicable during the initial "long-term" period
may no longer be an appropriate basis for decision making;
•	Projected doses that exceed the dose constraint may be of a magnitude similar to
doses from natural sources of radiation;
•	At some point beyond about 10,000 years, possibly as long as 1 million years,
comparison of projected doses with the safety criteria cannot provide useful
information.
Logically, if at times longer than about 10,000 years, projected doses that exceed the initial
dose constraint are not indicative of unacceptable performance and can still be consistent
with principles of intergenerational equity, it follows that a longer-term dose constraint
(representing a level not to be exceeded) can be higher than the initial constraint without
violating those same principles.
We find a similar position expressed by the ICRP: "The dose/risk constraints should
increasingly be considered as reference values for the time periods farther into the
future.. .transgressions of constraints do not necessarily oblige rejection of a proposed
safety case, merely because their value is estimated to be exceeded... This must not be
misinterpreted as a reduction in the protection of future generations and, hence, a
contradiction with the principle of equity of protection, but rather as an adequate
consideration of the uncertainties associated with the calculated results." (Publication 81,
Paragraph 77, Docket No. EPA-HQ-OAR-2005-0083-0417, emphasis added)
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In conclusion, EPA remains committed to the principles of intergenerational equity.
However, we do not interpret these principles as requiring that the same compliance
standard must apply at all times (and, in particular, not at times in the extreme far future,
such as we are addressing in the amendments to 40 CFR part 197), and believe the
preceding discussion demonstrates that such a strict interpretation does not necessarily
comport with guidance from the very organizations that have largely defined these
principles as they apply to geologic disposal. We therefore conclude from this discussion
that having multiple dose standards applicable over different time periods is not a priori
inconsistent with the principles of intergenerational equity as set forth by IAEA. In
addition, the reasons stressed by IAEA and ICRP for viewing projections in the far future
as qualitatively different from relatively short-term projections are consistent with the
concerns we emphasized in limiting the compliance period to 10,000 years in our 2001
rule. We believe the approach we are adopting today, incorporating an initial dose standard
for the initial 10,000 years, with a separate standard applicable beyond that time and up to
1 million years, is valid and comports with the principle of intergenerational equity.
Section 9 Intergenerational Equity
Issue C: NAPA and KASAM reports
1.1 want to focus on intergenerational equity. One of you made the statement that you —
that the document, which we've been studying closely, founds itself, bases itself on the best
experts in the world. That's not true. That's not true at all.
It is true that in the field of environmental ethics, you will find controversy about
what kinds of obligations do we have toward future generations. And there are few who say
we couldn't have any because we don't even know who they could be. They may even be so
like ourselves, these folks argue, that we wouldn't know how to obligate ourselves or not to
where they may be very unlike ourselves. And then on what ground could you have an
obligation to even know what they're talking about? That's one school of thought. It's a
very small school of thought.
If you'd like to corroborate the statement that I just made, you cite the National
Academy of Public Administrators, Reference 1, Reference 2, Reference 3. Go look at
Reference 3, which is the — oh, no, Reference 1 in that book is the entertainer bibliography.
If you go to the first section, it's called Intergenerational Equity or Environmental Ethics —
one or the other. Anyway, that's where all
that stuff is.
And you'll see there a paragraph or so of summary of about 125 articles and books
in the field regarding this topic we're discussing right this minute. If you go through that
and simply check off which of those even addresses what we're talking about and then put
them in a column — yes, meaning that they hold to a certain view; and then no, if they don't
hold to that view — here's what you find: About 52 of them discuss the question of whether
we have moral obligations to future generations. About a half of eight, in other words
teeter-totter — maybe yes, maybe no. There's reasons here, those reasons there, so half and
half.
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There are eight articles that go half and half, so some weight toward the no. There
are 44 that say we do have moral obligations to future generations. So when you write, as
you did, that there is no consensus on the question in the literature, that is literally correct,
of course. However, it's disingenuous because, although there's no consensus, there is a
strong preponderance of conviction amongst all those you cite, or your citation cites that
scholars all over the world hold to the view. And Chapman and McCombie,who you cite
with the authority over and over and over, summarize this chapter and say the same thing,
mainly that the moral obligation that we have to those in the future is substantially the same
as the one we consider ourselves to have to each other here and now.
And if you look around this room at the ones who are still here, look at the irony of
this. Not one man or woman in this — today since 4:30, 5:00 o'clock has spoken on behalf
of him or herself for the present generation. So here you have an interesting falsification.
In other words, these people, who by your account probably diminish their sense of
moral responsibility the farther away the generation goes from here, from today, all of
these men and women have argued on the behalf of the Nevadans of 12,006. That's 10,001
years from now, 2005 plus 10,001 years. We've argued for them, not ourselves. How on
Earth could we do that if we feel nothing or if we feel that it's diminishing?
It's true your mathematics diminishes, granted. But what you've done is premise
your entire document on the claim that, as the mathematical predictability of quantitative
dosage standards diminishes with increasing uncertainties and a cross-plain of uncertainties
going out, therefore, the moral responsibility does the same thing. We don't hold that view,
we don't hold that view. We hold the view, for example, that murder is wrong. We don't
say that murder is wrong today, but a hundred years from now it will 93 percent wrong.
And then 20,000 years from today, it will be 41 percent wrong, and then 500,000 years
from today, it will be 11 percent wrong. We don't do that. Some things in
morality are wrong and some are right.
And the brotherhood and sisterhood of men and women has been held by every
religion and all of the philosophers as long as we have a history. And I'm talking the whole
world, and I'd be happy to give you citations and backup.
So it is simply not true that this diminishing moral responsibility standard that
you've used has the credential of being well-rooted in the history of religions and of
morality and debate amongst ethicists around the world. We don't hold those views.
It's true, yes, there are huge complexities about resources and degrees of
responsibility and how could you acquit yourself of your responsibility. And there's huge
questions about the sustainability of the institutions. How can you ascertain any standard if
the institutions themselves go to pot? You don't even address that. You have no discussion
in the document about process, about democracy, about how to give these things moral
legitimacy. And like those who follow us, you should have. (Comment 0209.16-1)
2. EPA's proposed rule also reflects a basic philosophical misunderstanding of
intergenerational equity. Principles of intergenerational equity traditionally have been
designed to protect future generations from unfairly bearing the burdens of current
generations' activities. For example, EPA stated that "we should not knowingly impose
burdens on future generations that we ourselves are not willing to assume." 66 FR 32107;
see also Appendix D. Yet EPA apparently would turn that notion on its head, implying that
intergenerational equity is a justification for, rather than a bar to, subjecting future
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generations to burdens that our generation has never been willing to impose upon itself. In
the name of intergenerational equity, EPA suggests that it may appropriately impose
contamination levels beyond anything our generation accepts for itself, and to do so for a
period that is orders of magnitude longer than the entire history of human civilization. See
Figure 1, supra (graph showing the duration of the period of median doses close to 350
millirem/year); compare EPA, Response to Comments at 3-8 (2001) ("no regulatory body
we are aware of considers doses of 150 mrem to be acceptable") (emphasis added). This is
as rational as invoking the Christian Golden Rule to justify theft. As discussed in detail by
Professor Fleming, the traditional premise of nuclear waste regulation has been that current
generations do owe duties to future generations, and that those future generations should
not suffer harms greater than those risked by the generations that actually derive the
benefits from nuclear activities. Intergenerational equity is a constraint, not a license for
current regulators to do whatever they please. Even the obscure sources EPA selectively
cites cannot sustain its implied contrary theory. See Appendix D (characterizing EPA's
choice of sources as "cherry- picking"). First, the National Academy of Public
Administration ("NAPA") report does not support EPA. That report recommends a
"sustainability principle" that "no generation should deprive future generations of the
opportunity for a quality of life comparable to its own." While the report also recommends
that "each generation's primary obligation is to provide for the needs of the living and next
succeed ding generations" and that "near-term hazards have priority over long term
hypothetical hazards," these recommendations are premised on the need to avoid trade-offs
where present generations suffer an injustice, and on the concept of a "rolling present"
which requires each generation to provide the next with the opportunity to reevaluate
decisions and make changes. EPA never explains how its proposed two-tiered standard can
be reconciled with those principles, and indeed it could not. EPA has identified no injustice
the present generation would suffer were EPA's standard consistent, and thus NAPA's
former premise for favoring current generations does not exist. Nor can EPA provide any
opportunity for future generations to revisit the burdens EPA now proposes to impose, and
thus the ability to create a "rolling present" does not exist. (Comment 0226-64)
3. EPA's other key source—a 1998 document by the Swedish National Council for Nuclear
Waste ("KASAM")—contains none of the propositions for which it is cited. In response to
questions from Nevada regarding where in KASAM's report any of these statements
existed, EPA conceded that they did not exist, and advised that the relevant comments
instead came from another Swedish paper published in 2004 that is not yet publicly
available in English. EPA then provided Nevada with an English language translation of
only one chapter of that document (chapter 9), which EPA claims supports its position.
Read in context, neither Chapter 9 nor the full 2004 Swedish document even remotely
supports EPA's proposal. Chapter 9 does describe a "minimal principle of justice"—as
Appendix D points out, it is apparently the only discussion of that purported minimal
principle—but the principle, as stated, does not support EPA's theory at all. Instead, the
authors state that if we accept the minimal principle of justice as a reasonable principle for
environmental ethics, it will have clear consequences for the nuclear waste issue. Thus, we
are obliged to use nuclear power today in a manner that does not harm future generations—
even if those generations are very distant. We cannot escape from our obligations just
because they have to do with the very long-term consequences of our actions. OAR-2005-
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0083-0197, at 429. The Principle of Minimal Justice applies for an unforeseeable period of
time in the future and, quite simply, means that as long as living creatures exist on this
planet, we have an obligation to not do anything that today that could jeopardize their life
and health in the future. Id. at 445. ... Therefore, on the basis of this principle, the
specification for the repository should be completely clear: We must build a repository that
can protection [sic] human beings and other living organisms for hundreds of thousands of
years into the future - or for as long as we can anticipate that the waste is hazardous. Id. at
446. Paradoxically, uncertainty concerning the future state of society, technology and
knowledge clearly provides us with clear guidance for how we, today, must design a
repository in a morally responsible manner. It must be designed so that, without controls
and corrective measures, it can protect the human beings who will live in its vicinity from
about the year 2050 and a couple of hundred of thousand year s in the future. Id. at 447
(italics in original.) (Comment 0226-65)
4.	The Principle of Minimal Justice requires that, with our technology, we do not
jeopardize future generations' possibilities for life. First andforemost: Do no harm. This
means that we should only construct a repository if we know that it is safe enough to
protect future generations. Id. at 449. This discussion is impossible to reconcile with the
principle EPA purports to extract from this document. The authors quite clearly do not
believe that current regulators have license to do whatever they please so long as they do
not compromise future generations' prospect for survival. Instead, they state that any
repository must "do no harm" "for as long as we can anticipate that the waste is hazardous."
Id. The remaining sources EPA cites also provide no support for its implied but
unarticulated intergenerational equity position. For example, EPA cites several sources for
the principle that long-term numeric projections are of less value, and implies that these
somehow bolster its suggested theories of intergenerational equity. Those general
statements, however, do not rebut the clear findings of the NAS that long-term numeric
projections for Yucca Mountain will have value and should be the proper basis for a
compliance assessment. Several of the sources EPA cites suggest that numeric assessment
is inappropriate only in post-/??/V//o/7-year time periods—a proposition irrelevant to EPA's
current decisions about assessing compliance in the post-10,000-year period. And even the
2004 KASAM report Chapter 9, from which EPA purports to extract a highly permissive
principle of intergenerational ethics, is clear: "To refrain from long-term assessments on
account of the difficulty of making them can never be considered to be a reasonable level
of ambition." Id. at 446 (quoting KASAM, Nuclear Waste - Research and Technique
Development 32 (2002). (Comment 0226-66)
5.	What EPA does not state in is that the first requirement and assumption in the KASAM
report is that a candidate repository site will be shown to provide permanent isolation of the
waste. Terms such as minimal and weak principles of justice relate to how
intergenerational issues are considered, not to justify taking a huge toll on the health of our
future generations. (Comment 0257-3)
6.	Is there also an implicit hope that future generations will forgive us for failing them?
Yes, it seems the hope is that, although a "weak principle of justice" is all we can muster,
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future generations will not care too much, and we will be safely removed from their blame.
(Comment 0267-4)
7.	How can we make decisions that will serve humanity and the Earth for a million years or
more? The proposed rule in the August 22, 2005 Federal Register does contain the answer
to that question, but it is not the proposed double standard. Instead, it is summed up on
page 49035, a citation of the principles set forth by the National Academy of Public
Administration (NAPA) in its 1997 report "Deciding for the Future: Balancing Risks,
Costs, and Benefits Fairly across Generations." (Comment 0267-6)
8.	The argument that follows this citation in the rule proposal is puzzling as a justification
for the double standard: "Application of the NAPA principles would lead each generation
to an approach that would best address the problem without unduly limiting the options
available to succeeding generations to modify that approach or to take other actions to
address their needs." In other words, if we take care of ourselves, it is up to successive
generations to take care of themselves. But the very premise of permanent waste disposal is
its irrevocability. "Each generation" that succeeds this one will have no "option to modify"
whatever approach we take. Instead of shifting the responsibility to future generations, the
NAPA principles tell us that if we take irrevocable action we must get it right. This is
especially true when we know very well that the long-term hazards are anything but
hypothetical—they are real and inevitable. (Comment 0267-7)
9.	Specifying a million-year compliance period shifts priorities in favor of hypothetical
hazards in the far distant future and it does so at the expense of today's near-term, concrete
used fuel disposal needs. Hence, the proposal fails to satisfy the "chain of obligation"
principle. (Comment 0298-3)
10.	The dilemma presented by a million-year standard is therefore this - it requires analysts
to venture into an unprecedented world of hypothetical speculation in the name of
protecting individuals 25,000 generations in the future from an underground hazard that is
no more significant than what already exists in nature. The placement of a requirement for
such esoteric long-term speculation in front of a program of near-term national importance
represents an extreme skewing of priorities in the wrong direction - directly opposite what
is intended by the "Chain of Obligation" principle. Consistent with this principle, EPA
should be placing a greater emphasis on the health and safety of current and near-term
generations than on that of far future generations about which little can be known. But this
proposal gives deference to the latter by placing a speculative million-year analysis at the
front end of a rigorous licensing process that must be completed as a prerequisite to the
implementation of the nation's vital used fuel disposal program - making it an issue that
will have a significant impact on the nation's used fuel management system. (Comment
0298-7)
11.	EPA's existing 10,000-year standard satisfies all four of the principles articulated by
The National Academy of Public Administration (NAPA), as cited by EPA, for balancing
risks, costs, and benefits fairly across future generations. (Comment 0298-10)
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12.	The plan inexcusably calls for a relaxing of the radiation standards over time, putting
future generations - and the fragile web of life - at risk. I am disturbed by the concept of a
"sliding scale" of moral responsibility over time that is discussed in the proposal. And I
believe that a "weak" or "minimal" principle of justice is not an acceptable principle to
apply to any generation, now or in the future. To discount the value of future generations
and knowingly allow increased exposure to radiation and potentially increased cancer rates
is wrong, plain and simple. Every generation deserves a strong principle of justice, and I
urge you to set radiation standards that protect the health of communities, wildlife,
groundwater, and the land - now and in the future. (Comments 0305-1 and 0348-1)
13.	One of the arguments used by the EPA is a conclusion from The Swedish National
Council for Nuclear Waste (KASAM) which "...concludes that increasing uncertainties
'means that our capacity to assume responsibilities changes with time. In other words, our
moral responsibility diminishes on a sliding scale over the course of time' (page 49036,
Federal Register, 8-22-05). However, KASAM and the EPA do not supply any evidence or
justification to back up the notion that our responsibility for future generations should
diminish with time. In fact, the radiation standard should become more stringent in the
future because of the inevitable corrosion which will effect the nuclear waste casks over
time. This disregard for future generations is not acceptable to the values of the Big Pine
Paiute Tribe. Human actions today must take into account serious and life-threatening
effects on future generations, no matter how far into the future. (Comments 0360-3 and
0363-3)
14.	The million year standard, we believe, does not meet the chain of obligation
requirement. This is defined as each generation's primary obligation is to provide for the
needs of the living and succeeding generations. Near-term concrete hazards have a priority
over long-term hypothetical hazards. Specifying a million year compliance period shifts
priorities in favor of hypothetical hazards in the far distant future and it does so at the
expense of near-term concrete waste disposal needs today of a significant national
importance. (Comment 0368.8-3)
15.	Underpinning this overall approach is a faulty assumption that we can apply different
principles of justice to different generations. The EPA instead introduces a sheer cliff at
10,000 years that moves from a strong principle to a minimal principle. In effect, the EPA
is arguing that uncertainties suddenly arises at 10,000 years but then disappears from
10,000 years to a million years. As a result, the people living 10,000 years from now will
be protected by a strong standard while those living 10,001 years from now will not.
(Comment 0368.10-3)
Response to Issue C:
Issue B of this section discussed the concept of intergenerational equity as it is expressed in
the fundamental radioactive waste management safety principles endorsed by IAEA ("The
Principles of Radioactive Waste Management," Safety Series 111-F, 1995, in particular
Principles 4 and 5, respectively, Docket No. EPA-HQ-OAR-2005-0083-0053, which relate
to protection of future generations and burdens on future generations, respectively). We
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also briefly discussed in our proposal documents prepared by the National Academy of
Public Administration (NAPA) and Swedish National Council for Nuclear Waste
(KASAM) (Docket Nos. EPA-HQ-OAR-2005-0083-0077 and 0197, respectively). NAPA
is a Congressionally-chartered organization whose purpose is to provide assistance to
government in assessing and effectively addressing issues of governance, including future
implications of contemplated actions. KASAM was created by the Swedish government in
1985 to provide an independent review of issues related to nuclear waste. The documents
are summarized in the following paragraphs.
The NAPA and KASAM documents20 provide examples of ethical and decision-making
constructs that take a middle ground between the bounding positions that either our
obligations to future generations are unwavering regardless of when they might live, or that
there are no obligations to future generations, save perhaps for those immediately following
our own. Both documents also focus on issues related to radioactive waste management,
which has typically considered intergenerational equity over time frames far in excess of
those addressed in other public policy contexts. However, NAPA examines these issues in
the specific context of remediation of radiologically-contaminated DOE sites, while
KASAM's examination is directly concerned with intergenerational equity as it relates to
geologic disposal. Still, we believe the views expressed by the NAPA committee are
relevant to the process of establishing regulatory standards applicable for times on the order
of 1 million years. As the NAPA committee stated, "these principles are not limited in
their value to the specific task set for the Academy by DOE. They can serve as a prototype
for many public programs which have intergenerational consequences, and provide an
ethical and philosophical starting point for many such public concerns."
Both documents firmly establish that there are obligations to future generations, but offer
somewhat different frameworks for defining the level and strength of those obligations.
NAPA's approach is based on an articulation of obligations to future generations, but
provides for the use of balancing considerations to inform decision-making. NAPA defines
four basic principles:
•	Trustee: Every generation has obligations as trustee to protect the interests of
future generations;
•	Sustainability: No generation should deprive future generations of the opportunity
for a quality of life comparable to its own;
•	Chain of Obligation: Each generation's primary obligation is to provide for the
needs of the living and succeeding generations. Near-term concrete hazards have
priority over long-term hypothetical hazards;
•	Precautionary: Actions that pose a realistic threat of irreversible harm or
catastrophic consequences should not be pursued unless there is some
countervailing need to benefit either current or future generations.
20 "Deciding for the Future: Balancing Risks, Costs, and Benefits Fairly Across Generations," 1997; and
"Nuclear Waste, Ethics, and Responsibility for Future Generations," Chapter 9 of "Nuclear Waste State of the
Art 2004," respectively
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These principles outline a hierarchy of responsibilities, which can be influenced by factors
such as the action we propose to take, the justification for that action, and its potential
effects on future generations. The more significant the effects of an action on future
generations, the stronger its justification must be. If a contemplated action may result in a
hazard to future generations, but failure to take that action will definitely have negative
effects on the current and succeeding generations, the action may be justified. An action
that will present a hazard to future generations may also be justified if the known near-term
hazard is judged to be equivalent or greater. However, if that action is likely at some point
in the future to (for example) cause widespread damage or death, create a high incidence of
acute or chronic illness, or render significant areas uninhabitable for long periods of time,
the action should only be taken if it is necessary to avoid problems of a similar nature, if
not magnitude, in the near term.
An important aspect of the NAPA approach is its reliance on the "rolling present," as
incorporated into the Chain of Obligation. This requires recognition that current
generations either may not have the information or ability to make a decision, or that future
generations may have cause to revisit decisions that are made. Similar to IAEA's Principle
5 in this regard, current generations must not simply pass their problems along to the next
generation (no generation could then be expected to take action if passing the problem
along was a viable option), but must provide resources and knowledge to help that
generation continue implementing policies or reach its own decisions.
KASAM takes a different view, and in fact finds a logical disconnect in reconciling
NAPA's principles. For example, KASAM questions how the "opportunity for a quality of
life comparable to its own" for future generations can be preserved if the "primary
obligation is to provide for the needs of the living and succeeding generations." Further,
while NAPA presents balancing factors to guide decision-making, KASAM focuses more
on the strength of obligations to future generations. KASAM identifies three "principles of
justice" that convey our responsibilities in the context of geologic disposal:
•	Strong Principle of Justice: We have an obligation to exploit or consume natural
resources in such a way that subsequent generations can be expected to achieve an
equivalent quality of life to ours. This principle can be discharged for 5 or 6
generations, or about 150 years.
•	Weak Principle of Justice: We have a moral obligation to exploit natural resources
in such a manner that not only the present generation but also future generations
can satisfy their basic needs. This principle can be discharged for an additional 5
or 6 generations, or out to about year 300.
•	Minimal Principle of Justice: We have a moral obligation to exploit or consume
natural resources in such a way that we do not jeopardize future generations'
possibilities for life. This principle applies at all times.
In this construction, these obligations become more limited over time, primarily because
our ability to identify the needs of future generations becomes more limited. As a result,
"our capacity to assume responsibilities changes with time. In other words, our moral
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responsibility diminishes on a sliding scale over the course of time."21 Therefore, in the
KASAM view, it is not so much a matter of the justification for the actions we are
contemplating, and the potential effects of those actions on future generations, as our
ability to relate to those generations in the first place that defines our obligations.22 As a
result, KASAM sees that our obligations quickly become "minimal." This leaves open the
question of whether our obligations would remain "strong" if only we were able to
understand the needs of future generations, or whether other considerations would then
become relevant. KASAM suggests that our ability to positively influence the future is
much more limited than our ability to negatively influence it, and that this might also be a
factor in defining the strength of obligations. NAPA agrees that "it is impossible for
members of the current generation to know the lifestyles, concerns, and preferences of
future generations." However, this is not seen by NAPA as a reason to make choices that
limit the options of future generations, or to assume a lesser obligation based on the
passage of time.
It should be understood that both NAPA and KASAM approach their principles from a
much broader perspective than we are able to exercise in establishing health and safety
standards. Both documents incorporate wider considerations of safety in determining an
overall course of action. NAPA is explicit, for example, in suggesting that "near-term
concrete hazards" may outweigh "long-term hypothetical hazards." Similarly, KASAM
suggests that our obligation to provide safe disposal through isolation of the waste may
outweigh our obligation to allow future generations the option to take a different action by
retrieving the waste. KASAM also considers that intergenerational equity begins with the
decision to use nuclear power, and it is incumbent on the generation making that decision
that it be applied in a way that does not result in "harm" to future generations. There is, of
course, also the argument that the uncertainties involved in evaluating the safety of
geologic disposal are best addressed by a program of interim or retrievable storage until
those uncertainties can be resolved. We have already noted that such considerations are
outside the scope of our action and authority.
21	This view was first expressed in KASAM's 1998 State of the Art Report to describe "the dilemma with
which we are confronted, based on the realisation of the long-term effects of our actions. On one hand, we
cannot renounce our responsibility for these actions. On the other hand, we cannot, at the same time, refrain
from a responsibility to fulfil our basic obligations to the current generation...A prerequisite for this is a basis
for decision-making that enables us to make a reasonable assessment of the consequences. Inevitably in this
situation, we are confronted by a time limit. This limit is set by the human capacity to imagine - anything
exceeding the bounds of human measurement cannot be comprehended by humans. The limit is also imposed
by the fact that the uncertainties of our base of knowledge, which include the capacity to determine the
durability of the system's technical design, increase as a function of the increasing timespan-perspective. The
degree of credibility in the material used as a basis for decision-making diminishes also over the course of
time. Science too, has its limits of credibility. This means that our capacity to assume responsibility changes
with time. In other words, our moral responsibility diminishes on a sliding scale over the course of timeP
(pp. 26-27, emphases in original) The point here is that, as consequences become farther removed in time
from our actions, it becomes increasingly difficult to say anything meaningful about how we might have
altered those consequences (other than perhaps not taking action at all). That is, it becomes more difficult to
relate the outcomes to decisions we made. This may be true as well if succeeding generations continue on the
same course of action, presumably modifying decisions we made.
22	For example, the KASAM document takes the position that people living in the 19th century would have
had a better basis to project the needs of our generation than would people in the 16th century, therefore the
"moral responsibility" to protect our needs would also have been greater.
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Similarly, the impact of our standards on future generations must also be viewed in a
limited way. Incorporated into both the NAPA and KASAM approaches is a distinction
between the significance of those potential effects on future generations. These effects are
characterized by terms such as "quality of life," "basic needs," "interests," and "possibility
for life," all of which are open to interpretation, not to mention more stark terms such as
"irreversible" or "catastrophic."23 KASAM provides some perspective by defining "basic
needs" to include such things as "food, water, energy, housing, health care and education."
Thus, we can envision a continuum of obligations to future generations. At one end of the
spectrum is the idea that our actions should not prevent future generations from achieving a
quality of life comparable to our own. We can perhaps equate "quality of life" with
"interests" as representing something beyond or in addition to basic needs, such as better
food or housing, wealth, jobs that do not demand hard physical labor, leisure time, or
access to entertainment. Toward the center of the continuum is the requirement that we
take no action that would limit those generations' ability to obtain their basic needs or
necessities, and at the other end is the more limited goal of not affecting their potential for
life itself.
We are establishing 1 mSv/yr (100 mrem/yr) as the public health and safety standard to
apply for the period beyond 10,000 years and up to 1 million years. We have determined
100 mrem/yr to be protective of public health and safety as a peak dose standard for the
Yucca Mountain repository. As discussed in the preamble to the final amendments,
international organizations such as ICRP, IAEA, and NEA recommend 100 mrem/yr as an
appropriate standard as an overall public dose limit in planning for situations where
exposures may be reasonably expected to occur. Domestically, both NRC and DOE
incorporate the 100 mrem/yr level into their systems of regulation (10 CFR 20.1301 and
DOE Order 5400.5, respectively), and NCRP also endorses the ICRP system of protection
(NCRP Report 116, "Limitation of Exposure to Ionizing Radiation," Docket No. EPA-HQ-
OAR-2005-0083-0407). This standard will protect public health and safety for up to 1
million years, and will also protect the needs and aspirations of future generations.
Many commenters disputed our interpretation of the NAPA and KASAM documents (70
FR 49035-49036), or took issue with the documents themselves. Commenter 0226 argues
that our discussion of the Chain of Obligation principle as formulated by NAPA ("Each
Generation's Primary Obligation is to Provide for the Needs of the Living and Next
Succeeding Generations. Near-term Concrete Hazards Have Priority Over Long-Term
Hypothetical Hazards.") is misleading, as we have not explained the "near-term hazards"
that must be balanced by a higher long-term standard ("EPA has identified no injustice the
present generation would suffer"). The commenter argues that we should not, and in fact
are not allowed to, consider the potential failure of Yucca Mountain to be licensed as a
"near-term hazard." The commenter further argues, in an attached appendix (discussed in
more detail in Issue D of this section), that once we deem 350 mrem/yr "acceptable," we
can no longer frame this as a "hypothetical hazard" for periods beyond 10,000 years.
23 The Joint Convention on the Safety of Spent Fuel and on the Safety of Radioactive Waste Management
(discussed in Issue B of this section) introduces another term as an overall objective that "the needs and
aspirations of the present generation are met without compromising the ability of future generations to meet
their needs and aspirations." (Chapter 1, Article 1, Docket No. EPA-HQ-OAR-2005-0083-0393)
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However, we did not propose to determine our standard by enumerating "concrete" and
"hypothetical" hazards. Our statutory role under the EnPA is to establish public health
protection standards for the proposed repository at Yucca Mountain. Congress established
the national policy of geologic disposal, and Congress is the appropriate venue for
considering the hazards, costs, and benefits in deciding on such a policy. Our rulemaking
does not consider factors outside the scope of the Yucca Mountain disposal system.
Therefore, we did not point to specific imminent hazards to public health or the
environment that require immediate movement of the waste, which we assume is meant by
the commenter. Nor did we, as suggested by Commenter 0215, consider the potential for
increased use of nuclear power to offset the effects of climate change, which the
commenter suggests could ultimately increase the quality of life for future generations.
Such considerations are not relevant to our rulemaking. Our single firm citation of the
Chain of Obligation Principle perhaps could have been better framed, as the appendix
submitted by Commenter 0226 puts it, as a question of our capacity to ensure that an
equivalent level of protection can be provided to the current and all future generations
(echoing the questions posed above, "what form can assurances of protection take, and can
they provide the same level of confidence?"). (See Issue D of this section for discussion of
the commenter's appendix.) We expressed the view that establishing a 15 mrem/yr
standard throughout the period of geologic stability would put far-future generations'
interests above those of current and succeeding generations (70 FR 49040). We believe
this to be true because of the uncertainties influencing dose projections. We believe the
NAS committee, with numerous references to "bounding" approaches, also recognized that
the assessments would effectively become more stylized as the compliance period
increased, and that a compliance standard applicable at times approaching 1 million years
might be different in some significant respects from its recommendations. We emphasized
that it was not a question of whether that level of performance could actually be achieved,
although as noted in Section 2, Issue B of this document, geologic disposal has always had
the recognized potential for doses exceeding 15 mrem/yr in the far future. Rather, we
believe a 15 mrem/yr standard over the period of geologic stability would not adequately
recognize the changing basis for regulatory decision-making. Ultimately, we believe we
have developed standards that are protective of public health and the environment,
meaningful, implementable, and provide a reasonable test of the disposal system that is
consistent with the NAS Report, D.C. Circuit decision, and the principles of reasonable
expectation. In our view, an unchanging 15 mrem/yr standard would not present a
reasonable test when applied for up to 1 million years.
Commenter 0226 also takes issue with our discussion of the KASAM Minimal Principle of
Justice, highlighting the statement that "we should only construct a repository if we know
that it is safe enough to protect future generations." The commenter states that our
conclusions "are impossible to reconcile" with this principle. Commenter 0257 similarly
points out that the underlying assumption in the KASAM report "is that a candidate
repository site will be shown to provide permanent isolation of the waste." An important
question that is not addressed by either commenter is, how is "safety" determined at
various times in the repository's evolution? We have discussed in detail in Section 4, Issue
A, of this document the approaches taken internationally to making such a determination.
It should be clear that in Sweden, "safety" becomes more subjective as time passes, e.g., it
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may be acceptable at longer times to exceed the compliance level established for the first
1,000 years ("[i]f the calculated risk exceeds the criterion.. .the underlying causes of this
should be reported on," but this is not necessarily cause for rejection). (Docket Nos. EPA-
HQ-OAR-2005-0083-0047 and 0388) Beyond 100,000 years, "a strict quantitative
comparison of calculated risk in relation to the criterion for individual risk in the
regulations is not meaningful." Why that level is exceeded, by how much, and how much
emphasis can be placed on quantitative dose projections changes over time, as it must.
Consistent with direction in the EnPA and the NAS recommendations, we have not taken
such an approach.
Commenter 0226 goes on to criticize our statements regarding the utility of dose
projections at long times. These statements "do not rebut the clear findings of the NAS that
long-term numeric projections for Yucca Mountain will have value and should be the
proper basis for a compliance assessment." The commenter then points out that some
references refer only to projections after 1 million years ("irrelevant to EPA's current
decisions") and cites the KASAM report: "To refrain from long-term assessments on
account of the difficulty of making them can never be considered to be a reasonable level
of ambition." We agree, which is why we required such assessments in our 2001
rulemaking. We also repeat a statement from our proposal (70 FR 49035), which the
commenter also cites: "In view of the way in which uncertainties generally increase with
time, or simply for practical reasons, some cut-off time is inevitably applied to calculations
of dose or risk. There is, however, generally no cut-off time for the period to be addressed
in some way in safety assessment, which is seen as a wider activity involving the
development of a range of arguments for safety." (NEA 2004, Docket No. EPA-HQ-OAR-
2005-0083-0046, p. 39, emphasis in original)
However, we disagree with the thrust of the comment and believe the commenter is
confusing the concepts of dose assessments and dose standards. We believe we accurately
represented international sources on both points. These sources do generally take the
position that numerical assessments eventually lose their utility (e.g., "calculations of dose
and risk should not be extended to times beyond those for which the assumptions
underlying the models and data can be justified," NEA, cited at 70 FR 49027). This
sentiment is in complete agreement with NAS statements regarding geologic stability:
"After the geologic environment has changed, of course, the scientific basis for
performance assessments is substantially eroded and little useful information can be
developed." (NAS Report p. 72, see also Section 10 of this document) However, even for
shorter periods when assessments can provide insights into disposal system performance,
the typical approach internationally is not to hold the results of those assessments to strict
numerical limits, but to view them more as qualitative indicators of performance (see, for
example, 70 FR 49026-49027).24 This approach acknowledges that the nature of dose
24 NEA notes: "There is agreement that calculations of dose and risk in the future are illustrations of possible
system behaviour rather than predictions of outcomes, and there is consensus that, in the long term, numerical
criteria for radioactive waste disposal should be considered as references or indicators, addressing the
ultimate safety objectives, rather than as absolute limits in a legal context." ("Regulating the Long-Term
Safety of Geological Disposal: Towards a Common Understanding of the Main Objectives and Bases of
Safety Criteria," NEA-6182, Docket No. EPA-HQ-OAR-2005-0083-0408, p. 24)
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projections changes over time, so that comparison of those projections to strict numerical
limits may not be the most meaningful indicator of equity over long time frames. We
recognize that NAS recommended an assessment of compliance against a numeric standard
at the time of peak dose (risk). However, as noted above, we believe NAS also recognized
that dose projections would effectively become increasingly stylized, and emphasized
"bounding" approaches and "quantifying" uncertainties for that reason, while making no
recommendation on the level of the peak dose standard, or even putting forward a range for
that final standard based upon scientific considerations, leaving the final decision as the
policy matter the committee believed it to be. (NAS Report pp. 5 and 20) We have already
discussed the NAS recommendation, placing it in its original context of judgment against a
probabilistic critical group, a less conservative receptor than the RMEI.25 Even in that
context, the committee indicated that a compliance standard that changed over time could
be a valid expression of intergenerational equity. (NAS Report pp. 56-57) As described in
the preamble to the final amended standards, the chair of the NAS panel expressed his
personal concern that our proposal would be too conservative had we adopted the 15
mrem/yr standard for the entire period of geologic stability. (Docket No. EPA-HQ-OAR-
2005-0083-0380) We have worked to develop a standard in which projections could be
reasonably used to assess compliance as the NAS intended, taking into account the factors
affecting both the compliance standard and the usefulness of projections at very long times.
From these perspectives, the 100 mrem/yr level is comparable to the range of risks
represented by domestic and international regulations suggested by NAS for EPA to
consider, "all of which are consistent with recommendations from authoritative radiation
protection bodies," and among which was the ICRP-recommended 100 mrem/yr public
dose limit. (NAS Report p. 49 and Tables 2-3 and 2-4) The nominal annual risk of fatal
cancer associated with 100 mrem/yr, 5.75 x 10"5, is a reasonable level of risk when the
significantly extended time frames considered in this rulemaking, with the attendant
uncertainties, are taken into account. We conclude that our final standards will protect
public health and safety, as required by the EnPA, and represent a valid and appropriate
expression of intergenerational equity.
Commenter 0298 argues that a standard applicable for 1 million years, regardless of its
level, will violate the principle of intergenerational equity. "The placement of a
requirement for such esoteric long-term speculation in from of a program of near-term
national importance represents an extreme skewing of priorities in the wrong
direction.. .this proposal gives deference to [far future generations] by placing a speculative
million-year analysis at the front end of a rigorous licensing process that must be
completed as a prerequisite to the implementation of the nation's used fuel disposal
program." The commenter goes on to state that our 2001 standards satisfied all four NAPA
principles and provide intergenerational equity.
25 In discussing an alternative subsistence-farmer receptor, the committee noted that "it makes the most
conservative assumption that wherever and whenever the maximum concentration of radionuclides occurs in
a ground water plume accessible from the surface, a farmer will be there to access it." (NAS Report p. 102)
We have defined the RMEI to incorporate this same assumption.
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Section 9 Intergenerational Equity
Issue D: State of Nevada Appendix D
1.	Having incorrectly determined that "uncertainty" renders impossible a traditional,
apportioned standard, EPA proposes that it needs an alternative, and that 350 millirem/year
is acceptable as a putative "policy" choice. But EPA offers no real explanation of why 350
millirem/year, which EPA does not consider acceptable today or 10,000 years from now,
should be considered acceptable after 10,000 years. EPA hints that principles of
intergenerational equity somehow support its proposed rule, but for a series of reasons, that
implication is illogical, unjustified, and ethically wrong. These flaws are explained in detail
in Appendix D, a white paper prepared by Professor Patricia Ann Fleming, Ph.D. Dr.
Fleming's full report must be considered. She considers the ethical implications of EPA's
proposed action and the ethical rationales EPA has stated, or implied, in support of that
rule, and concludes that EPA misconstrues accepted principles of intergenerational ethics,
mischaracterizes the sources upon which it relies, and has offered an incomplete and
internally inconsistent ethical rationale. (Comment 0226-59)
2.	Initially, EPA's discussion of intergenerational equity is fatally vague. EPA never
actually states what equitable principle it is adopting. Instead, EPA's proposed rule
provides a cursory, selective, and inaccurate survey discussion of a few intergenerational
equity theories, none of which EPA itself has ever adopted in the past. See Appendix D
(discussing EPA's selective use of sources and its mischaracterization of the limited set of
sources it does cite). EPA then hints at the notion that an action is equitable so long as it
does not impose catastrophic burdens upon future generations. EPA never clearly
articulates the principle it is endorsing, or explains why EPA considers that particular
principle to be just, equitable, or appropriate. That failure of explanation leaves
intergenerational equity as an improper basis for EPA's rule, for EPA cannot merely hint
that a policy justification for its proposed action might exist; it must actually articulate and
support its purported policy rationale. (Comment 0226-60)
Response to Issue D:
Commenter 0226 provided an appendix with extensive discussion of intergenerational
equity issues, many of which have been touched upon in Issues A-C of this section (the
appendix is in the docket at Docket No. EPA-HQ-OAR-2005-0083-0230). Professor
Fleming, the author of the appendix, generally finds our discussion lacking in clarity and
depth, when compared to the body of work on this topic. She also views our consideration
of the NAPA and KASAM document as questionable, finding that neither of these
documents is widely referenced in peer-reviewed literature. She also finds the viewpoint of
Chapman and McCombie in "Principles and Standards for the Disposal of Long-Lived
Radioactive Wastes" (Docket No. EPA-HQ-OAR-2005-0083-0061) to be "logically
problematic" in its "appeal to nature" as a guide for determining long-term acceptable
doses (a "fallacy" the author seems to find common in "the nuclear waste community").
We will address several specific aspects of this appendix here.
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First, Professor Fleming addresses the concept of the "rolling present" put forward by
NAPA, relating it to the concept of "institutional constancy" in an earlier KASAM report
(Nuclear Waste State-of-the-Art Report 1998, Docket No. EPA-HQ-OAR-2005-0083-
0056). It is argued that there is no opportunity for a "rolling present" in this case because
we have made no provision to review and update our standards as the state of knowledge
increases, "nor can EPA provide any opportunity for future generations to revisit the
burdens EPA now proposes to impose" (Comment 0226-64). We disagree. As pointed out
earlier, our standards are part of an entire framework established by Congress to implement
its chosen national policy, geologic disposal. Promulgation of our standards is not the final
opportunity for future generations to review this policy. We reserve the right to amend our
standards in the future if warranted. Similarly, NRC licensing would allow construction
and operation of the repository, but the waste must remain retrievable for a significant
period of time, likely to be at least several generations. Closure of the repository and
termination of the license also requires a demonstration to NRC of compliance with
regulatory requirements. Here we also think it appropriate to consider the other element of
intergenerational equity, which is the burden to be placed on future generations in
addressing past practices. The fundamental difficulty in addressing radioactive waste is
that regardless of the management method selected, succeeding generations will necessarily
assume some burden, by virtue of the long-lived nature of the hazard. Geologic disposal
has been seen as a way to make that burden minimal beyond the time necessary for
implementation, in that a goal of geologic disposal is to provide the necessary containment
and isolation without the continued commitment of resources for active maintenance or
even reliance upon future generations' knowledge of the facility. The requirement for
retrievability has been seen as a way not to foreclose the opportunity for newer technology
or better approaches to be identified by succeeding generations. By contrast, reliance on
continued storage, without an identified method of ultimate disposal, may reflect the
current generation's ability to address the problem, but has also been seen as an abdication
of responsibility in leaving it to future generations to find a permanent solution.
Any number of factors could influence national policy and the way Yucca Mountain would
be operated. For example, it has been proposed that a Global Nuclear Energy Partnership
(GNEP) be pursued that would emphasize advanced technologies for reprocessing spent
fuel and reactor designs that would result in less waste. Such an effort could significantly
affect the volume and characteristics of the waste needing disposal. (See the testimony of
Paul Golan, DOE Acting Director of the Office of Civilian Radioactive Waste
Management, before the Senate Environment and Public Works Committee, Docket No.
EPA-HQ-OAR-2005-0083-0380) Similarly, successful development of technology for
transmutation of long-lived isotopes could significantly reduce the time necessary for
isolation of waste. It is also possible for Congress to take specific action, as it did when it
directed us to develop site-specific standards for Yucca Mountain. Professor Fleming does
not believe this is sufficient, and suggests that an explicit requirement for review of the
Nuclear Waste Policy Act and all subsequent actions on a regular basis be implemented
(e.g., every 20 years).
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As a second point of interest, Professor Fleming recognizes valid ethical bases for
concluding that there is no obligation to future generations, and also discusses situations in
which current and succeeding generations would take precedence over future generations,
even if obligations are acknowledged to exist. Further, she concludes that we have not
followed the NAS direction to "as a matter of policy address whether future generations
should have less, greater, or equivalent protection." (NAS Report p. 56) Our proposal is
criticized for not "muster[ing] arguments in support of the [greater or equivalent
protection] positions and then explaining] why the 'lesser duty position' is morally
preferable." As noted above, we do not question that there are obligations to future
generations in the management of radioactive waste, as stated in the IAEA Principles of
Radioactive Waste Management, both in terms of impacts to future generations and in the
burdens placed on those generations for waste management. Professor Fleming makes the
distinction between "basic needs" and "welfare interests" (or "wants"). When the needs of
current and future generations are in conflict with respect to a specific action, the most
difficult ethical decisions must be made. Where needs are in conflict with wants, however,
needs must always be given precedence. She characterizes the current situation as the
"wants" of current generations to pursue geologic disposal resulting in denial of "needs" of
future generations through a higher peak dose standard. She concludes that "[t]he multiple
dose protection standard proposed by the EPA jeopardizes future humans' possibilities for
life." We do not believe this is a reasonable conclusion. We are not, however, establishing
the proposed level as the final peak dose standard. We are instead establishing a level of 1
mSv/yr (100 mrem/yr) as the public health and safety standard to apply for the period
beyond 10,000 years and up to 1 million years. As discussed in the preamble to the final
amendments, the dose level of 100 mrem/yr is well-established as protective of public
health, and as such represents a robust standard for public health protection in the extreme
far future. International organizations such as ICRP, IAEA, and NEA recommend its use
as an overall public dose limit in planning for situations where exposures may be
reasonably expected to occur. Domestically, both NRC and DOE incorporate the 100
mrem/yr level into their systems of regulation (10 CFR 20.1301 and DOE Order 5400.5,
respectively), and NCRP also endorses the ICRP system of protection (NCRP Report 116,
"Limitation of Exposure to Ionizing Radiation," Docket No. EPA-HQ-OAR-2005-0083-
0407). We believe it provides, as Professor Fleming cites, "the same opportunity that we
have had to live healthy, happy, and satisfactory lives."
We have, of course, concluded that a higher standard is appropriate to address the
uncertainties inherent in projecting doses for periods approaching 1 million years.
Professor Fleming points out that time is generally not considered an ethically acceptable
reason for diminished protection for future generations. That is, we should look at any
future generation, even one presumed to live 1 million years from now, as we would look
at our own children: "The chain of obligation does not weaken our duties to future
generations; it does just the opposite: it establishes those duties as equally strong across
generations." Thus, time "does not change the strength of the moral duty we have to
provide equal protection from harm (no matter how 'negligible') to their basic need for
health." We do not believe, however, that the time frames under consideration in geologic
disposal are as easily accommodated by this concept.
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Finally, Professor Fleming makes a distinction between our obligation to future generations
and our capacity to discharge those obligations. In other words, we may not be able to
assure the same level of protection for all generations, but if we were able to do so, would
we consider it a moral obligation? By its very nature, geologic disposal extends this
question to time frames not considered in other contexts. If a fundamental principle is that
it cannot rely on continued maintenance, geologic disposal cannot be implemented without
projecting the performance of the disposal system, developed using current knowledge and
technology, over times far in excess of those considered in other applications. As the time
covered by the assessment increases, the confidence that the current knowledge base is
representative of "real" conditions at such times necessarily diminishes, and assessments
effectively become more stylized. If as a result, the basis for decision-making also
changes, it must be considered whether equivalent protection can be demonstrated at times
as far removed as 10,000 and 500,000 years, and whether that demonstration is as simple as
a comparison of dose or risk constraints, especially if at later times they are considered as
"indicators" or "reference levels".26
Professor Fleming suggests that the "rolling present" is the way to acknowledge that future
generations may have a greater capacity to address the issue than we do, and that we do not
"reduce [duties] or weaken them because of uncertainty associated with time." The author
also states that NAS "rejected" uncertainty in compliance assessments as a reason for "not
providing guidance beyond 10,000 years." However, the question is not one of providing
guidance. We addressed earlier the distinction between conduct of dose assessments and
establishment of dose standards. The French and Swedish approaches discussed in Section
4, Issue A of this document provide significant guidance on long-term projections. We
provided guidance for post-10,000-year projections in our 2001 rule, and could have
provided additional guidance regarding long-term features, events and processes (FEPs),
similar to that in our current rulemaking. The distinction is that NAS recommended
assessing compliance against a standard at the time of peak dose (risk). As we have stated
elsewhere, this approach is atypical in the international community. We believe it has
always been implicit in the concept of geologic disposal that it may not be possible to offer
assurances of equivalent protection to all future generations, and that the potential exists for
doses to at some point exceed those considered acceptable today, in spite of our best efforts
(see Section 4, Issue A of this document, as well as Section 2, Issue B). We note that the
recently approved IAEA Safety Requirements for Geological Disposal of Radioactive
Waste (WS-R-4), which represents a consensus document of member states, includes the
following statement: "In very long timeframes.. .uncertainties could become much larger
and calculated doses may exceed the dose constraint. Comparison of the doses with doses
from naturally occurring radionuclides may provide a useful indication of the significance
of such cases." (Docket EPA-HQ-OAR-2005-0083-0383, paragraph A.7, p. 37) This
26 NEA observes these difficulties: "The design and implementation of a repository involves balancing of
risks and responsibilities between generations. The obligations of the present generation toward the future are
complex, involving not only issues of safety and protection but also of freedom of choice and of the
accompanying burden of responsibility, and of the need to transfer knowledge and resources. Our capacity to
deliver these obligations diminishes with distance in time, which complicates the setting of criteria to be used
today in order to demonstrate that obligations to the future will be met." ("Regulating the Long-Term Safety
of Geological Disposal: Towards a Common Understanding of the Main Objectives and Bases of Safety
Criteria," NEA-6182, 2007, p. 25)
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statement clearly indicates that projected doses that would be unacceptable in the near term
may be acceptable at later times, which would be difficult to reconcile with the IAEA's
own principle that "predicted impacts on the health of future generations will not be greater
than relevant levels of impact that are acceptable today" (Docket No. EPA-HQ-OAR-2005-
0083-0390, p. 6) unless it is accepted that either "future generations" does not mean "all
future generations" or that the uncertainties involved in dose projections make such direct
comparisons less meaningful at longer times. See Issue B of this section for discussion of
the IAEA principle.
We have taken the latter position, which we believe to be consistent with the consensus
international views, and have developed standards that are protective of public health and
the environment for all generations during the period of geologic stability, while addressing
the issue of long-term uncertainties in projecting performance. NAS itself "recognize[d]
that there are significant uncertainties in the supporting calculations and that the
uncertainties increase as the time at which peak risk occurs." (NAS Report p. 56) We
believe NAS anticipated that assessments would effectively become more stylized at longer
times, leading to its many references to "bounding" approaches and "quantifying"
uncertainties. NAS concluded that uncertainties could be sufficiently bounded to make
compliance assessments feasible, but implicitly considered in its discussion of
intergenerational equity the possibility that a standard applicable at the time of peak dose
might differ from its recommendations in some important ways. (NAS Report pp. 55 and
56-57) We noted in our proposal that ICRP took a similar view in its Publication 81,
"Radiation Protection Recommendations as Applied to the Disposal of Long-Lived Solid
Radioactive Waste," stating that "as the time frame increases, some allowance should be
made for assessed dose or risk exceeding the dose or risk constraint. This must not be
misinterpreted as a reduction in the protection of future generations and, hence, a
contradiction with the principle of equity of protection, but rather as an adequate
consideration of the uncertainties associated with the calculated results" (Docket No. EPA-
HQ-OAR-2005-0083-0087). Determining whether a dose limit is adequately protective of
both current and future generations must also consider the ability of performance
assessments, and those who interpret them, to distinguish between differing repository
designs, as well as different conceptualizations of total system performance over very long
time frames. In our view, it makes little sense to assert that a 15 mrem/yr dose limit for the
period within 10,000 years is more "protective" than a higher limit much later in time if, in
the time frame of hundreds of thousands of years, the uncertainties in projecting disposal
system performance cannot easily make distinctions at such incremental levels. Where
fundamental uncertainties have significant effects, decisions about overall safety based on
incremental doses may be less supportable.
As noted earlier, NAS indicated that a dose standard changing over time could be a valid
expression of intergenerational equity. However, as pointed out by Professor Fleming,
NAS also stated that "EPA should as a matter of policy address whether future generations
should have less, greater, or equivalent protections." (NAS Report p. 56) This is a
particularly challenging request, given that our task is to identify a specific numerical
standard of safety against which the performance of the disposal system will be judged for
up to 1 million years. However, the fact that one approach may be justified and consistent
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with the objectives of intergenerational equity does not automatically mean that it should
be preferred over other approaches that may be equally justified and consistent with those
objectives. Consistent with the strictest interpretations of IAEA Principle 4 (see Issue B of
this section), we have essentially accepted the obligation to provide current levels of
protection at Yucca Mountain for 10,000 years, as we did with our original 40 CFR part
191 standards. To say that people beyond that time "should" have lesser protection
involves either a judgment that the pursuit of geologic disposal takes precedence over
future generations, which we have already concluded is outside our purview, or a judgment
that our obligation is somehow changed. On the other hand, it may not be possible to
provide the same level of protection, even if we believe it "should" be provided. Whether
that "should" then automatically cause a rejection of the safety case is another question. As
we interpret the IAEA statements, it should not.
Further, it is not clear that the relative equity of different standards can be judged by a
simple comparison of the allowable doses. We discuss in the preamble to the final
amended standards, and in Sections 2 and 4 of this document, the personal Senate
testimony of NAS committee chair Robert Fri. As we noted in those discussions, he
stressed the importance of the receptor in constructing the standards, and indicated that the
connection between the receptor and the compliance period may affect the level of
conservatism in the dose projections (i.e., in his view, the RMEI effectively becomes a
more conservative receptor as the compliance period is extended from 10,000 to 1 million
years). As a result, he suggested that a 15 mrem/yr peak dose limit in our rule could be
viewed as "overly conservative" from the NAS perspective and not consistent with the
intent of the committee. In such a case, it must be considered whether such a conclusion
would have implications for the appropriate expression of the principle of intergenerational
equity. The importance of these remarks is in the recognition that judgments of
"conservatism" or "equity" must be based on the overall character of the assessment, which
is not determined by the dose standard alone.
We have provided generations up to 10,000 years with the same level of protection
applicable to current activities. However, as the time period covered by the assessment
increases, the level of uncertainty in dose projections increases, so that they can no longer
be viewed in the same way. Without a comparable basis for judgment, the "protection"
offered by the standard at widely varying times cannot be directly equated, even if the dose
standard is the same. Our ability to provide assurance of protection in that sense is
similarly diminished. It is not clear how comparison of "protection" can be made under
such circumstances, although we conclude that, far from offering "equivalent protection," a
15 mrem/yr peak dose standard would be unreasonably restrictive and demand more than
can be reasonably expected from performance assessment models when large uncertainties
are present. In such a case, the protectiveness of the long-term standard on its own merits
assumes primary importance. We can say with confidence that the 100 mrem/yr peak dose
standard being established today will protect public health and safety for the period
between 10,000 and 1 million years, and protection comparable to that provided by the 15
mrem/yr standard for the first 10,000 years, even if it is not possible to state that the
protection is equivalent in all respects (or, indeed, whether it is greater or less) to the 15
mrem/yr standard applicable for the first 10,000 years.
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Section 10 Compliance Period
1.1 protest the folly of this EPA proposed public health standards for the planned high-
level radioactive waste disposal facility at Yucca Mountain, Nevada to attempt to protect
public health for 1 millions years. It is not within the foreseeable future scientific
capabilities to identify all possible adverse geologic and societal events that may occur
in the next million years; much less to take actions that will protect public health. I do not
know the source of the desire to protect the population of southern Nevada a million years
from now. The idea of 1 million year public safety protection is pure folly and a waste of
public funds. This EPA concept for public health should be dismissed as unreasonable and
arbitrary and without foundation. (Comment 0090-1)
2.	Whichever standard is applied it should be applied for all time. At no time now or in the
predicted future should the release of radioactive materials be allowed to exceed these
levels. (Comment 0091-3)
3.	This proposed 1,000,000 year criterion is ridiculous and should not be promulgated. This
will unnecessarily increase the cost of nuclear waste disposal. If other technologies were to
be held to this standard, technological progress would cease. No doubt this is the desire of
the uninformed eco-zealots who try to pawn this on us in the name of protection. Common
household waste disposal does not even meet this standard. EPA must establish reasonable
standards. Known civilization has only existed a small fraction of this proposed time. It is
unreasonable to doubt that if we allow it to progress, that technologically advanced society
could not solve any unlikely problems that result from this waste storage a thousand years
from now. (Comment 0093-1)
4.1 find the extension of the time from for the Yucca Mountain rules to one million years
to be absolutely preposeterous. The rules should apply no longer than the current life of the
nation, about 200 years. By then, the people of the US, if such still exists, will probably not
even be able to read, much less interpret, the rules. This is silliness in the extreme.
(Comment 0094-1)
5. "NAS recommended standards that would apply to the time of maximum risk and stated
that there is "no scientific basis for limiting the time period of the individual-risk standard
to 10,000 years or any other value." The above statement is irrelevant with respect to the
health and safety of the public. 10,000 years is a convenient threshold regardless of what
the NAS or Nevada has to say. NAS and Nevada are entitled to an opinion. The opinion of
both NAS and Nevada should be noted for the record, but rational decisions should made
by the EPA, even if they are not directly in line with the hypothetical arguments. If this
repository meets a 10,000-year criterion, then any rational adult would agree that is
adequate. The age of the nation for practical purposes is 229 years (2005 - 1776). One
million years translates to 4,367 times the age of the nation. To try to regulate anything to
this magnitude of time is fairy tale. To try to predict anything to this magnitude of time is
fairy tale. No nation has ever or will ever remain intact for this magnitude of time. To try to
regulate in this arena is simply foolish. I recommend that no time periods past 10,000
years be used. Common sense should prevail. (Comment 0095-1)
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1.	The proposed compliance period is too severe as no human being can predict, nor should
they attempt to regulate, outcomes past a few thousand years. The EPA should "Require
that the design of the repository have a reasonable chance of success in resulting in a
maximum dose of 15 mrem/year to the maximally exposed individual through 3000 years
following disposal, based on the assumption that engineered containment of radionuclides
will be successful in totally sequestering them for at least 1, 000 year." If you think about
it, 3,000 years is the time human beings have been recording their activities in writing. In
the past 10,000 to 15,000 years ice ages have occurred. It is arrogant for us to think we can
subject a project to such long term requirements as the EPA is proposing. (Comment 0110-
1)
2.	This weaker standard sets radiation exposure at 15 millirems for the first 10,000 years,
then increases to 350 millirems one day later. It is unprecedented for the to set expiration
dates for public health standards; however, this is exactly what the new EPA proposed
standard would do. (Comment 0111-2)
3.	As a scientist/engineer who has worked with government agencies over the years, the
thought that they can either assess and/or control and ensure the encapsulation safety of
emissive material for even 1,000 years, much less 10,000 or (choking back laughter) 1-
million years... .No, I can't agree with these changes since I believe that the continued lack
of competence already demonstrated gives one no confidence that the DoD/DoE/EPA are
capable of doing anything in this area properly. (Comment 0114-1)
4.	In addition, while a de facto time period of 10,000 years has been established
internationally for protection from radiation, no such standard exists for any other toxic
material or other risk. (Comment 0209.9-3)
5.	Ten thousand years is an unimaginably long period of time for regulatory compliance.
While NARUC does not agree that an extension beyond 10,000 years is warranted, we
recognize the EPA has to comply with the D.C. Circuit's instructions on remand.
(Comment 0217-3)
6.	EPA's proposed rule presumes that the period of geologic stability is 1,000,000 years.
While this may prove to be a reasonable limit to the performance assessment, what NAS
actually said was that the period of geologic stability was "on the order of 106 years." NAS
Report at 69. The rule should not absolutely preclude consideration of time scales in excess
of 1,000,000 years if justified by considerations of geologic stability and the need to assess
long-term performance of the natural barriers. (Comment 0226-118)
7.	EPA is apparently aware that in the proposed rule, the true compliance period effectively
ends at 10,000 years. In its discussion of deteriorating repository performance, the
proposed rule notes that "[i]f such a dramatic deterioration were projected to occur close to
the regulatory time period it would be a more pressing concern for licensing decisions than
if it were to occur many hundreds of thousands of years into the future (remembering that
the uncertainty in performance projections increases with time)." 70 Fed. Reg. at 49028
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(emphasis added). The reference to the "regulatory time period" in this sentence, contrasted
with a point of time hundreds of thousands of years in the future, would be
incomprehensible if EPA believed that the real compliance period extended through the
period of peak dose. (Comment 0226-121)
8.	Inclusion of any numerical 10,000 year dose standard is unnecessary, inappropriate and
detrimental to the environment. The NAS report allowed the EPA to make decisions on the
standard on policy matters and I believe that the 15rem/yr 10,000 year standard is
sufficiently protective and all that is needed. EPA should, as a matter of policy, not
technical bases, conclude that there is no need for a post 10,000 year standard. No other
toxic materials are regulated beyond the 10,000 year period. Radiation has been on the
earth since the earth began and Neanderthals roamed the earth just 30,000 years ago.
Compliance projections beyond 10,000 years are not meaningful because of the
uncertainties involved. They have little societal usefulness, except possibly to reject any
repository site due to excessively expensive unendingly complicated regulatory
proceedings. Society's resources would be much better utilized in addressing other more
urgent environmental issues than arguing about multi hundred thousand year dose
projections. (Comment 0264-2)
9.	While in general I agree with the proposal put forward, I have some serious concerns
about the usefullness of protection standards for periods far into the future. The reliability
of projections even to 10000 years are hardly more than guesses as to the performance of
the repository system. (Comment 0277-1)
10.	All of these regulations should have the caveat of "as long as reasonably possible"
added to them, in the event that current systems of government and regulation alter or cease
to exist at some future time. (Comment 0277-3)
11.	EPA has proposed standards that, from a conceptual standpoint, are protective of public
health and safety. Yet, while promulgation of these standards represents progress toward
the important national goal of safe and effective disposal of used nuclear fuel and other
high-level radioactive byproducts, it does not constitute the most effective implementation
of the court's mandate. Industry strongly believes that extending the repository regulation
beyond 10,000 years does not represent sound public policy or effective regulation.
Therefore, the nuclear energy industry opposes this proposal. (Comment 0298-1)
12.	NEI reminds EPA that the court specifically offered the agency two possible
approaches to address its finding. The first is the option that EPA has chosen, which is to
revisit the standards. The second is to clarify the basis for the compliance period of 10,000
years either by seeking legislation from Congress, as the court specifically suggested, or
alternately by following the roadmap for addressing the policy aspects of this issue also
provided by the court. Although EPA has chosen to extend the compliance period, this is
not the best way to address the court mandate. Since EPA has chosen to revisit the
standard, NEI recommends that the agency follow the roadmap the court provided in its
decision to overcome the deficiencies in the original rulemaking process and finalize the
proposed standards so a 10,000-year period is retained. The legislative histories of the 1992
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Energy Policy Act and 2002 Yucca Mountain Development Act clarify the intent of
Congress to apply a 10,000-year compliance period for the Yucca Mountain repository.
(Comment 0298-2)
13.	Congress foresaw this potential problem in 1992. This is why Congress, through the
EnPA, instructed the NAS to develop recommendations on "reasonable standards"
including answering the question of whether or not the probability of human intrusion
breaching the repository could be predicted "over a period of 10,000 years." In equating
"reasonable" with 10,000 years in this instance, Congress was on very solid footing. The
necessity of limiting regulatory compliance periods to reasonable lengths of time is widely
recognized in the international regulation of hazardous material disposal. (Comment 0298-
6)
14.	Conversely, a 10,000-year standard provides ample protection for future generations for
at least as far as we can reasonably foresee without placing an unreasonable burden on
current and near-term generations. Furthermore, EPA's existing requirement for an analysis
of longer-term performance in the Yucca Mountain Environmental Impact Statement
provides for a meaningful look into the far future, without imposing an unreasonable
quantitative compliance standard. EPA should heed its "great concern" about the
implementability of such a million-year standard and pursue the path that remains open to
clarify and reinforce its original policy decision to limit the period of regulatory
compliance to 10,000 years. (Comment 0298-8)
15.	EPA included a separate groundwater provision in 40 CFR 197 for policy reasons and
the court agreed with EPA's rationale for doing so. Seen in that light, a properly grounded
10,000 year compliance period would be acceptable. In fact, the court in NEI outlined a
roadmap for doing exactly that in suggesting that, by pegging the compliance period
initially to that time when radiation dose reaches its peak, EPA may then proceed to
methodically and logically develop a compliance period of 10,000-years.. .Properly
grounded on the Academy's findings and recommendations and explained, a 10,000-year
compliance period strikes an appropriate and proper balance between long-term coverage
and implementability. (Comment 0298-9)
16.	Such an approach, founded on the NAS's findings and recommendations, is not only
consistent with the decision in NEI, it reflects just what Congress had in mind when in
enacted the EnPA...In considering the Yucca Mountain Development Act, Pub. L. 107-200,
Congress was well aware of the 10,000-year period for evaluating compliance. No concern
was expressed with respect to this aspect of the Yucca Mountain program, nor was there
any indication that such a period was at odds with what was envisioned in the EnPA or the
subsequent NAS report. The NAS report itself, recognized that it was addressing only
scientific matters and that EPA's rulemaking — even as it accepted the NAS's scientific
views — could well be driven by policy considerations as well as pure science. (Comment
0298-11)
17.	One important caution regarding any effort to set a dose limit a million years into the
future is that just because the level chosen takes into account the inevitable variability of
analytical results in the face of long-term uncertainties (while still being safe) does not
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mean that the analysis, or any regulatory decision based upon it, will be meaningful. The
reason for this is that there is a difference between precision and accuracy. While our
analytical tools may be precise enough to evaluate radiation exposures to within hundreds
of millirems a million years in the future, that still does not mean that the result will be
accurate in any meaningful way. No matter how carefully we seek to be reasonable in
defining assumptions, there is simply too much about the next million years that is not
knowable, including the evolutionary status of the human race. Therefore, not only do we
take no position on EPA's proposal of 350 millirems per year, but we would be unable to
support any number EPA might choose. Again, we do not believe that the establishment of
any quantitative regulation looking one million years into the future represents sound
public policy. (Comment 0298-15)
18.	We recommend that the new EPA radiation protection standard should remain in effect
in perpetuity with no time limit. (Comment 0326-3)
19.	Duke considers the key element of EPA's proposed standards, the million year dose
limit for Yucca Mountain, to be inappropriate. The time frame involved is simply too long
for effective regulatory implementation. One million years is orders of magnitude longer
than the span of human civilization, and the changes that the world will see over that time
span are impossible to reliably predict. A limit on projected doses for one million years
would be a regulatory paperwork exercise, not a measure that protects public health and
safety. Duke believes that EPA's previous regulatory framework, i.e., a 10,000 year
standard with a requirement to assess longer time periods in an environmental impact
statement, was a reasonable and protective approach. Rather than promulgating a million
year standard, Duke advises EPA to address judicial concerns by providing policy
justification for the 10,000 year standard. If EPA should choose to promulgate a million
year standard, the approach outlined in the proposed revision to 40 CFR Part 197 is
generally reasonable. However, as noted above, the concept of the million year standard is
inherently flawed, so there can be no good way of implementing it. (Comments 0330-1
and 340-1)
20.	We further assert that it is futile and also foolish to try to plan complete protection for
even the most exposed individual so far in to the future. Such an effort is completely
inconsistent with the amount of effort expended on avoiding present and near term risks.
For example, toxic substances, such as other heavy metals, are not even regulated for
10.000	yeas. If with present knowledge of climate and geology we are not setting up future
populations for undue risk, that should be sufficient. (Comment 0350-2)
21.1	believe that the 15 mrem/yr 10,000 year standard is sufficiently protective and all that
is needed... .there is no need for a post 10,000 year standard. (Comment 0351-2)
22. The proposed EPA rule presents an appropriate blend of technical and policy
considerations to address the Committee recommendation that compliance with an
individual radiation protection standard extend through the time of geologic stability,
which, for Yucca Mountain, the Committee found to be on the order of one million
years.. .Extending the regulatory period to address doses at the time of peak risk has the
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potential to introduce arbitrary and unbounded speculation into the assessment of
repository performance.. .In developing a regulation that deals with this unprecedented
time period, EPA has quite properly considered not only the time period but also the related
elements of the regulation, including: the level of protection, the requirements for the
performance demonstration, and the appropriate statistical measure of performance. There
is no scientific or policy basis for a presumption that a standard that is appropriate for
10.000	years would necessarily be appropriate for a time scale up to 100 times longer, with
proportionately greater uncertainties. (Comment 0352-2)
23.1	think that trying to set standards for a 10,000 year period is pretty iffy under the best
of circumstances with the best of scientists with the best intentions. I think it's admirable to
have some standards to try and (unintelligible) to try and set standards for a million years, I
think passes ridiculous and I would hope that any standard that the EPA does set is
(unintelligible) because things will change so much (unintelligible). (Comment 0364.1-1)
24.	.. .the industry strongly believes that extending the repository regulation beyond 10,000
years is not sound public policy nor effective regulation. We, therefore, oppose the
standard. (Comment 0368.8-1)
25.	NEI recommends that EPA follow the road map that the court provided in its decision
to overcome the deficiencies in the original rule making and finalize the currently proposed
standards so that the 10,000 year period is retained. The legislative history supporting both
the 1982 "Energy Policy Act," which set this regulation in motion, and the 2002 "Yucca
Mountain Development Act" approving the site for further development and licensing
makes clear that Congress meant for the compliance period to be limited to 10,000 years.
The agency should act immediately to either seek clarification from Congress or reassert
the original policy of 10,000 years as I have described. (Comment 0368.8-2)
Response to Section 10:
Many commenters consider the idea of regulatory standards applicable for 1 million years
to be unrealistic. Various commenters characterized our proposal to regulate to such times
as "folly," "unreasonable and arbitrary and without foundation," "ridiculous," "absolutely
preposterous," "silliness in the extreme," "a fairy tale," "simply foolish," "arrogant,"
"unnecessary, inappropriate, and detrimental to the environment," "a regulatory paperwork
exercise," "inherently flawed," "futile and also foolish," and "passes ridiculous." Some
view 10,000 years with similar skepticism, and recommend a much shorter compliance
period. Others recognized our reasons for making such a proposal, but disagreed that it
was necessary to address the Court decision. A few commenters stated that the standards
should apply beyond 1 million years.
Regarding periods beyond 1 million years, Comment 0326-3 states that the standard (at a
level of 10-30 mrem/yr) "should remain in effect in perpetuity with no time limit."
Similarly, Comment 0091-3 states, "Whichever standard is applied it should be applied for
all time," although the commenter believes that the 15 mrem/yr standard is not protective,
and should be reduced to 2.5 mrem/yr or even lower.
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Comment 0226-118 notes that "what NAS actually said was that the period of geologic
stability was 'on the order of 106 years.' The rule should not absolutely preclude
consideration of time scales in excess of 1 million years if justified by considerations of
geologic stability and the need to assess long-term performance of the natural barriers."
Our final standards incorporate a compliance period of 1 million years, and no compliance
standard applies to projected doses beyond that time. As with our 2001 rule, NRC will
have to make judgments regarding the overall safety of the disposal system over very long
times. We have not specified standards to apply beyond 1 million years, which we believe
reasonably implements the NAS recommendation by equating 1 million years with the
period of geologic stability, for the purposes of regulatory decision-making. We took
NAS's phrasing of "on the order of' in the more colloquial sense of "approximately" (NAS
Report p. 72) or "about" (NAS Report p. 85), rather than as a statement regarding "order of
magnitude," as some have suggested. We note also the phrasing on page 91 of the NAS
Report, where the committee again addresses the "boundability" of factors "in performance
assessments that extend over periods on the order of about 106 years." (emphasis added)
We believe our decision to define the period of geologic stability as ending at 1 million
years is appropriate from a regulatory policy perspective and justified by site-specific
scientific information. More discussion of geologic stability and our reasons for setting a
regulatory time limit at 1 million years may be found at the end of this section and in of the
preamble to the final rule.
The same commenter (in Comment 0226-121) suggests the "true compliance period" is still
10,000 years, citing references to the "regulatory time period" in our proposal. The
commenter finds this "incomprehensible if EPA believed that the real compliance period
extended through the time of peak dose." The commenter neglects the context in which
these statements appear (70 FR 49028, Docket No. EPA-HQ-OAR-2005-0083-0042). The
discussion addresses NRC's judgments using "reasonable expectation" as a guide to
reaching its decisions. The paragraph preceding that cited by the commenter frames the
context as "40 CFR part 197 as originally promulgated" and notes elements of regulatory
compliance determinations left to NRC specification. The statement highlighted by the
commenter refers to the difficulty presented in the licensing decision if "dramatic
deterioration" is seen at a particular time in the future, which is generally true regardless of
the length of the compliance period. That difficulty would certainly be enhanced if such
deterioration appeared shortly after the end of the compliance period, rather than in the
very far future. The following sentence reinforces the context: "With the initial issuance of
40 CFR part 197..." The next paragraph states "We propose to continue this general
approach of not specifying the bases or mechanisms for a compliance decision, except that
the post-10,000-year analyses are now proposed to be part of the 40 CFR part 197
standards with a quantitative limit imposed" (emphases added). We recognize that similar
NRC judgments may be involved in evaluating projected doses shortly after 10,000 years
under our final amendments, when the long-term peak dose standard of 1 mSv/yr (100
mrem/yr) is in effect. Theoretically, "dramatic deterioration" after 1 million years would
also be of concern. However, we do not believe similar conclusions can be drawn or
supported regarding the nature of disposal system evolution at such different times, nor do
we believe it is appropriate to attempt such evaluations beyond 1 million years. We
recognized in our 2001 rule that significant loss of containment within the initial 10,000-
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year period, or shortly thereafter, would be potentially more significant, and required that
longer-term projections be placed in the EIS to provide more complete information. By
contrast, maintaining substantially complete containment until late in the 1 million-year
compliance period or beyond would be indicative of a repository operating at a much
higher level of performance.
Some commenters proposed alternatives for the period of compliance. Comment 0094-1
points out that the United States has only existed as a nation for about 200 years, and
suggests this as an appropriate regulatory timeframe, since "the people of the U.S., if such
still exists, will probably not even be able to read, much less interpret, the rules."
Comment 0095-1 accepts the 10,000-year period, but similarly notes that "[t]he age of the
nation for all practical purposes is 229 years. One million years translates to 4,367 times
the age of the nation.. .No nation has ever or will ever remain intact for this magnitude of
time." Comment 0110-1 recommends a compliance period of 3,000 years, "the time
human beings have been recording their activities in writing," "based on the assumption
that engineered containment of radionuclides will be successful in totally sequestering them
for at least 1,000 years." Several other commenters expressed skepticism about the 10,000-
year timeframe, but did not offer a specific alternative. For example, Comment 0114-1
questions the premise that even 1,000 years is achievable because "the continued lack of
competence already demonstrated gives one no confidence that the DoD/DoE/EPA are
capable of doing anything in this area properly." Comment 0277-1 characterizes
projections to 10,000 years as "hardly more than guesses." Comment 0364.1-1 likewise
states that "trying to set standards for a 10,000-year period is pretty iffy under the best of
circumstances with the best of scientists with the best intentions." We recognize that the
complexities involved in projecting performance for 10,000 years may not be fully
appreciated when consideration of such times has become routine in radioactive waste
disposal applications, and when the focus is shifted to times out to 1 million years.
However, we have always applied the "reasonable expectation" approach to emphasize that
"proof' of performance cannot be provided in the usual sense. Nevertheless, we believe
that, in general, 10,000 years remains a reasonable period of regulation during which
mathematical modeling of the disposal system can provide significant insights into its
behavior (for example, its response when thermal stresses are most significant) and can
serve as a basis for regulatory decision-making. We believe international experience,
including that at WIPP, supports this approach.
Many comments expressed opinions that the idea of predicting conditions around the
repository, or society in general, as well as disposal system performance and dose
projections, over a period of 1 million years is untenable (Comments 0090-1, 0093-1,
0094-1, 0095-1, 0110-1, 0113-15, 0277-1, 0298-15, 340-1, 350-2, and 0364.1-1). The time
frame for societal planning and forecasting is typically in the range of hundreds of years.
Some comments point out that few nations have remained intact beyond a few hundred
years without suffering periods of significant lapse in stable government, and that the
history of organized societies only extends for thousands of years. These observations lead
many commenters to conclude that attempting to "regulate" for 10,000 or 1 million years is
simply a meaningless concept. We acknowledge the difficulties and uncertainties in
making such predictions far into the future and we have attempted to factor these
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considerations into our standard. But we do not think the effort is meaningless. NAS
clearly voiced the opinion that uncertainties are boundable and manageable and that
performance assessments projections to the time of peak dose could be meaningful and
useful for compliance decisions. We concur with this general finding and have included
provisions in our final rule that we believe effectively respond to uncertainties and will
make the compliance determination more meaningful.
Some comments expressed a concern that a compliance period of one-million years, from a
societal perspective, was untenable because there is no certainty that an institutional
presence can be assumed to exist and to actively "regulate" the disposal system so far in the
future (Comments 0090-1, 0095-1, 0110-1, 0217-3, and 0227-3). These comments assert
that the time horizon for predicting societal change and institutional stability/controls is
only on the order of hundreds of years at most, and that the time frame for recorded history
is only in the thousands of years. We understand the perspective in these comments and
agree that an institutional presence far into the future cannot be assumed to be effective for
actively "regulating" the disposal system. This same sentiment can be voiced for a 10,000-
year compliance period as well. However, the intent of deep geologic disposal is to
develop a waste disposal system that will perform acceptably in the absence of human
monitoring and intervention. For the limited time frame of societal actions and stability,
requiring a demonstration of acceptable very long-term performance in a regulatory process
executed today is in essence an exercise of good engineering practice in a regulatory
context. The tool for assessing performance of a deep geologic repository are the
performance assessment calculations specified in the standard, i.e., the engineered
repository is designed, in combination with the natural barrier, to perform acceptably over a
period far in excess of what could reasonably, or even optimistically, deemed to be the
period of institutional control, and therefore the time that government institutions can be
expected to persist and to enforce regulations.
The fact that the demonstration relies upon modeling of the components of the disposal
system that cannot be confirmed through measurement or observation introduces
uncertainty into the judgment, but also ensures that each component will be subjected to
detailed scrutiny. The NAS pointed out that the assessments should focus on the period of
maximum risk whenever it occurs (within the geologic stability period), and our peak dose
standard addresses this recommendation by requiring a demonstration of acceptable
performance (disposal system performance assessments) over the period of geologic
stability. We recognize the significant uncertainties involved in this demonstration and we
believe we have constructed a reasonable test for repository performance at peak dose, as
described in the preamble to the final rule and other discussions in this document. We
believe that the peak dose requirement is sufficiently strict that the best science and
engineering, within restraints of resource limitations, will be applied to the disposal system.
NAS expressed a similar view in concluding that our standards need not address ALARA
principles: "it is nothing other than sound engineering practice to consider whether
reductions in radiation dose or risk can be achieved through engineering measures." (NAS
Report p. 125)
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We also received comments pointing out the disparity in regulation between radioactive
waste and other types of toxic materials. Comment 0093-1 states that "[i]f other
technologies were held to this standard, technological progress would
cease.. .technologically advanced society [will] solve any unlikely problems that result
from this waste storage a thousand years from now." This commenter and Comments
0209.9-3, 0264-2, and 0350-2 all made similar points that no other substances are regulated
for periods beyond 10,000 years, even when such substances, such as heavy metals, do not
decay over time. We used a similar justification in issuing our 2001 rule, citing this as the
specific example offered by the NAS committee regarding circumstances in which policy
considerations might justify a compliance period that did not extend to the time of peak
dose. However, the Court of Appeals did not accept this reasoning as providing
consistency with the NAS technical recommendation, rather than the committee's views on
policy; therefore, we have established a compliance period that extends up to 1 million
years.
Other commenters argued that we should try again to justify the 2001 standards as
consistent with the NAS recommendation regarding compliance at the time of peak dose.
Comment 0095-1 believes that the NAS statement regarding "no scientific basis for
limiting the time period of the individual-risk standard" is "irrelevant with respect to the
health and safety of the public." Further, "10,000 years is a convenient threshold
regardless of what the NAS or Nevada has to say" and that EPA should make "rational
decisions.. .If this repository meets a 10,000-year criterion, then any rational adult would
agree that is adequate." Comments 0298-1, 0298-2, 0298-15, and 0368.8-1 assert that our
proposal "is not the best way to address the court mandate" and "does not represent sound
public policy or effective regulation." The commenter refers to the legislative history of
the EnPA to support the contention that Congress intended a 10,000-year compliance
period and "was well aware of the 10,000-year period for evaluating compliance" when it
approved the site recommendation in 2002. The commenter recommends that we "clarify
and reinforce [our] original policy decision to limit the period of regulatory compliance to
10,000 years." To do this, we would follow the "roadmap" outlined by the court that
would begin with the NAS recommendation, "then proceed to methodically and logically
develop a compliance period of 10,000 years," which "strikes an appropriate and proper
balance between long-term coverage and implementability."
Our difficulty here, as we expressed in our proposal (70 FR 49032), is that we do not see
that the D.C. Circuit ruling presented us with a clear "roadmap" to justifying the 10,000-
year compliance period. We agree that the Court said it might have been a different case
had we started with the NAS technical recommendation, and addressed our policy concerns
from that starting point. Conceivably, that might have left us with a 10,000-year
compliance period, but that is not the only conceivable outcome. However, the Court was
not receptive to our policy arguments and reacted strongly to specific wording in our
rulemaking, which led it to conclude that we had disregarded the NAS recommendation.
We do not see a way of crafting the arguments that will dispel that impression, as the
commenter suggests. Ultimately, as we stated in the proposal, "it is not clear how EPA's
earlier explanation of its policy concerns might be reconciled with NAS's technical
recommendation." The commenter further points out that "EPA included a separate
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groundwater provision in 40 CFR Part 197 for policy reasons and the court agreed with
EPA's rationale for doing so. Seen in that light, a properly grounded 10,000-year
compliance period would be acceptable." We disagree that these situations are
comparable. The Court gave us deference to implement our ground-water protection
policies in 40 CFR part 197 precisely because the NAS made no recommendation
regarding such a standard, and our interpretation of the EnPA as providing us with the
authority to establish such a standard was reasonable. By contrast, the individual-
protection standard is at the core of the EnPA direction to us and the time over which
compliance with such a standard should be assessed is a focal point of the NAS
recommendations. Thus, the issue of consistency with NAS, which was the basis for the
Court ruling, is fundamental to one aspect and irrelevant to the other. Our policy
arguments have already failed to sway the Court. Therefore, we see extending the
compliance period as the most appropriate approach in view of the language in the Court's
decision and the weight accorded by the Court's decision to the committee's technical
recommendations concerning the period of geologic stability. We believe we have
appropriately "accommodated" our policy concerns in the provisions related to the peak
dose standard, statistical measure of compliance, and FEPs.
Comment 0277-3 suggests that we should recognize the potential for future changes (or
disappearance of) government and regulation. We are aware of the limitations of dose
projection methodologies and the inherent uncertainties in projecting behavior of a disposal
system over very long time frames, and we believe this understanding of uncertainty lies
behind the commenter's phrase, "as long as reasonably possible." However, we believe the
concept of geologic disposal already recognizes these potential changes. Licensing
decisions are predicated on the acceptability of projected doses into the far future, not on
what may be physically "possible" to measure or assess at various points in time. It is
well-recognized that human behavior cannot be projected with confidence for more than a
few decades to perhaps a hundred years into the future. A fundamental goal of geologic
disposal is to provide a level of containment and isolation that will protect future human
societies without imposing a burden on those societies to invest resources in maintaining
the repository, or rely on their continued knowledge of its existence. To that end, the
length of time for which institutional controls can be expected to prevent deliberate
intrusions into the repository is limited.
A few comments agreed that our approach is a reasonable way to address the Court
decision, even though they believe our 2001 standard included all that was necessary to
protect public health. Comments 0217-3, 0340-1, and 0352-2 expressed this opinion,
although, as Commenter 0340 put it, "the concept of the million year standard is inherently
flawed, so there can be no good way of implementing it." Comment 0298-1, while
disagreeing with the approach as discussed above, also stated that "from a conceptual
standpoint, [the proposed standards] are protective of public health and safety," although
"we [are] unable to support any number EPA might choose" to apply for 1 million years.
This commenter and Commenter 0352 also stressed the difficulties in assigning meaning to
very long-term projections. Comment 0298-15 notes the difference between precision and
accuracy: "While our analytical tools may be precise enough to evaluate radiation
exposures to within hundreds of millirem a million years in the future, that still does not
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mean that the result will be accurate in any meaningful way." Similarly, Commenter 0352
cautions that "[ejxtending the regulatory period to address doses at the time of peak risk
has the potential to introduce arbitrary and unbounded speculation into the assessment of
repository performance.. .There is no scientific or policy basis for a presumption that a
standard that is appropriate for 10,000 years would necessarily be appropriate for a time
scale up to 100 times longer." We discussed at length in our 2001 rulemaking and 2005
proposal our concerns regarding the usefulness of very long-term projections in making
regulatory decisions, which was a principal factor in limiting the compliance period to
10,000 years in our 2001 rule. We believe the overall approach we have taken in this final
rule to extending the compliance period appropriately considers these inherent difficulties
and results in standards that are protective of public health, meaningful, implementable,
and provide for a reasonable test of the disposal system that is consistent with the NAS
Report, D.C. Circuit decision, and the principles of reasonable expectation.
Regarding our decision to equate the period of geologic stability with 1 million years, and
to establish that time frame as the compliance period, we believe this is an appropriate
decision for both regulatory policy and scientific reasons. We believe our policy decision
is supported by NAS: "It is important, therefore, that the 'rules' for the compliance
assessment be established in advance of the licensing process." (NAS Report p.73). We
believe, therefore, as a matter of regulatory philosophy and policy, that a relatively loosely
defined stability period "on the order of' one million years is not sufficiently specific for
regulatory purposes, i.e., implementing our standards and reaching a compliance decision.
Indeed, NAS clearly considered that the compliance period could be one of the "rules" that
should be established for compliance assessments. (NAS Report p. 56) Comment 0226-
118 suggested that the period of geologic stability could be longer (or interpreted "on the
order of one million years" as possibly as long as ten million years), and said our rule
should allow consideration of longer timescales if justified by considerations of geologic
stability. The actual period of geologic stability at Yucca Mountain is unknowable, and we
disagree that an open-ended compliance standard is justified over such time frames. We
believe that the applicant (DOE) and the compliance decision-maker (NRC) must have
definitive markers to judge when compliance is demonstrated, and that a loosely defined
time frame does not provide such a marker for implementation of our standards in a
licensing process. We believe that the geologic stability period of 1 million years that we
have defined provides the necessary marker, and is within our discretion to set as a matter
of policy. (See generally NAS Report p. 3) To do otherwise we believe would leave the
licensing process in a potentially untenable situation of dealing with possibly endless
debate over exactly when a peak dose occurs in relation to a compliance period time limit.
Such debate can arise because of the inherent uncertainty that exists in characterizing the
complex processes and variables involved in projecting performance of the disposal system
over very long periods of time. As the NAS explained, "although the selection of a time
period of applicability has scientific elements, it also has policy aspects we have not
addressed." (NAS Report p. 56)
On this point, we are in general agreement with the international community, in which
there is widespread acceptance of the proposition that quantitative performance projections
at very long time frames have limited utility for regulatory decision-making, and that 1
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million years may be a reasonable reference point beyond which such projections either
should not be required or should be considered only in their broadest sense.27 However,
we believe it is also necessary to address NAS's scientific judgments regarding geologic
stability at Yucca Mountain.
While NAS did not define with precision the period of time that the geologic environment
likely would remain stable, for purposes of our regulation we believe scientific information
can be relied upon to support a firm definition of that period as ending at 1 million years
after disposal. Further, we believe that equating a specific time period with the "period of
geologic stability" is a site-specific decision, as NAS's statements regarding geologic
stability were wholly in the context of Yucca Mountain. (See, for example, NAS Report p.
69: "The time scales of long term geologic processes at Yucca Mountain are on the order of
106 years"; and NAS Report p. 85: "The geologic record suggests this time frame is on the
order of about 106 years"). Therefore, we have considered how the natural processes and
characteristics at the Yucca Mountain site would support defining the period of geologic
stability, for regulatory purposes, as ending at a specified time after disposal. In
considering the natural setting, many comments expressed the view that the site's natural
characteristics are so conducive to rapid release and transport of radionuclides, only the
waste packages and other engineered barriers would make it possible for significant doses
to be delayed much beyond 10,000 years. We believe it is therefore also appropriate to
consider the geologic stability period from the perspective of a reasonable length of time to
allow significant events acting on the waste packages and engineered barriers, and
ultimately leading to release of radionuclides, have a reasonable probability of occurring
within the designated time period. Natural processes and events would contribute to both
the package failures and to the subsequent transport of radionuclides, even if such failures
occur relatively late in the period under consideration. It should be clear that we are not
attempting to predict when geologic conditions at and around the site will have altered so
dramatically that today's understanding of the site would be irrelevant to the conditions at
such a time in the future. Rather, we view the period of geologic stability in this regulatory
context to be a period long enough for natural FEPs projected to occur during that period,
as defined by examination of the site's geologic record and the specifics defined in our
27 For example, in general guidance documents, the IAEA has stated that "little credibility can be attached to
assessments beyond 106 years." ("Safety Indicators in Different Time Frames for the Safety Assessment of
Underground Radioactive Waste Repositories," IAEA-TECDOC-767, p. 19, 1994, Docket No. EPA-HQ-
OAR-2005-0083-0044) In its final 2006 Safety Requirements for Geological Disposal of Radioactive Waste,
IAEA also states "Care needs to be exercised in using the criteria beyond the time where the uncertainties
become so large that the criteria may no longer serve as a reasonable basis for decision making." (Docket No.
EPA-HQ-OAR-2005-0083-0383, page 11, paragraph 2.12) As a country-specific example, final guidelines
from the Swedish Radiation Protection Authority state that "the risk analysis should be extended in time as
long as it provides important information about the possibility of improving the protective capability of the
repository, although at the longest for a time period of one million years." (Docket No. EPA-HQ-OAR-2005-
0083-0388) Also, in an example where the official guidelines specify a risk target that is of undefined
duration, the United Kingdom's National Radiological Protection Board has stated that "[o]ne million years
is... the timescale over which stable geological formations can be expected to remain relatively unchanged,"
while concluding that the scientific basis for risk calculations past one million years is "highly questionable."
("Board Statement on Radiological Protection Objectives for the Land-based Disposal of Solid Radioactive
Wastes," 1992 Documents of the NRPB, Volume 3, No. 3, p. 15, Docket No. EPA-HQ-OAR-2005-0083-
0416)
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rulemaking, to contribute to a reasonable test of the disposal system by having their effects,
if any, manifest themselves in the results of performance assessments during that period.
Engineered barrier performance is the factor leading to consideration of periods as long as
1 million years.
A consideration of the geologic history of the site, in the areas of igneous and seismic
activity, also supports a 1 million year stability period. Information compiled by the NRC
(Docket No. EPA-HQ-OAR-2005-0083-0373) concerning basaltic igneous activity around
the site shows that this type of activity has been the only activity around the site through
the Pliocene (beginning roughly 5.4 million years ago), and that the volume of eruptive
activity (both tuff and basaltic material) has decreased continually over the last 10 million
years (Coleman et al., 2004, Docket No. EPA-HQ-OAR-2005-0083-0378). From the
identification of surface features as well as indicators of buried remnants of past volcanic
activity, the episodes of basaltic activity around the site can be shown to have occurred in
clusters of events around 1 million and 4 million years ago (Hill, 2004, Docket No. EPA-
HQ-OAR-2005-0083-0373). The occurrence of these clusters indicates that the nature and
extent of past volcanic activity can be reasonably well characterized and that annual
probabilities for such events can be reasonably estimated from the geologic record around
the site. Annual probabilities of volcanic disruptions to the repository have been estimated
by various investigators, and range from as high as 10 6 to as low as 5.4 x 10"10 (Coleman
et al, 2004, Docket No. EPA-HQ-OAR-2005-0083-0378).
Further, while geologic stability may be viewed as being affected primarily by large-scale
events, accumulations of small-scale changes over very long time periods also have the
potential to alter the geologic setting and affect the technical basis for performance
assessments. Tectonic events have such a potential at Yucca Mountain. Rates of
displacement on the nearest potentially significant fault in the region average about 0.02
mm/yr. (DOE, Science & Engineering Report, 2002, p. 4-409, Docket No. EPA-HQ-OAR-
2005-0083-0069) This means that in 10,000 years, there could be 20 cm (0.65 ft) of
displacement, a relatively small change not likely to affect performance of the geologic
system. However, in 1 million years, the same rate of movement results in 20 m (65 ft) of
displacement on the fault. Using the larger estimates of movement within the range of
potential movement, displacement could be as much as 30 m (100 ft) over 1 million years.
Such changes in the geologic setting at Yucca Mountain have the potential to erode the
scientific basis for performance assessment and possibly to affect the quality of the
information the assessment can provide to decision-makers.
NAS also stated that "we see no technical basis for limiting the period of concern to a
period that is short compared to the time of peak risk or the anticipated travel time." (NAS
Report p. 56) This statement also suggests that the stability period must be long enough to
allow FEPs that pass the probability and consequence screens to demonstrate their effects,
if any, on the results of the performance assessments, even from waste package failures
occurring relatively late in the period. In contrast to the accumulated small-scale changes
discussed above, larger-scale seismic events are more likely to contribute directly to
radionuclide releases through the effects of ground motion. Strong seismic events could
damage waste package integrity by causing emplacement drift collapse or vigorous shaking
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of the packages themselves. It is known that damage to underground structures from
seismic activity is significantly less than damage to surface structures for earthquakes of
given magnitudes. Earthquake recurrence intervals for the site indicate that strong events
could reasonably be assumed to test waste package integrity at various times within the 1
million-year period (Docket No. EPA-HQ-OAR-2005-0083-0374 and EPA-HQ-OAR-
2005-0083-0379). The Yucca Mountain site is in a seismically active area and seismic
hazard curves have been developed for the area (Docket No. EPA-HQ-OAR-2005-0083-
0374). Studies of potential damage to emplacement drifts from seismic activity indicate
that the threshold for damage lies at the mean annual exceedance frequencies between 10"4
and 10"5 per year (Docket No. EPA-HQ-OAR-2005-0083-0379). This means seismic
events of sufficient magnitude to cause some damage to the repository itself have the
probability of happening once over the course of ten thousand to one hundred thousand
years. These exceedance probabilities correspond to earthquakes of approximately
magnitude 6 and above (Fig 2-10, Docket No. EPA-HQ-OAR-2005-0083-0374), with
ground motions varying between approximately 0.5 and 1.6 g (Fig. 2-12). Estimates of
maximum earthquake magnitudes (magnitudes 7.5-8) in the area around Yucca Mountain
(Fig 2-10) show that the annual exceedance probabilities for these high-end events are in
the range of 10"5 and below. (Such an event would have the potential of happening on
average once every 100,000 years.)
There is considerable uncertainty in estimating the annual exceedance probabilities for
these very low probability, high-magnitude seismic events, and in estimating their actual
potential for adversely affecting repository performance, as can be seen by inspecting
Figures 2-10 and 2-12 from the DOE report cited above (Docket No. EPA-HQ-OAR-2005-
0083-0374). We make no judgments on the evaluations of potential damage from these
low-probability high-magnitude events. We do believe that, considering the high degree of
uncertainty involved in evaluating their occurrence and effects, a 1 million-year stability
period provides a time frame long enough for a reasonable test of their projected effects on
waste packages and the overall performance of the disposal system.
In addition, we note that estimates of ground-water travel time from the repository to the
RMEI location are on the order of thousands of years (see the BID for the 2001 final rule,
Docket No. EPA-HQ-OAR-2005-0083-0050). At these rates, releases affected by
disruptive volcanic and seismic events would not be delayed from reaching the RMEI
location during the stability period, e.g., added releases from a low probability seismic
event at 800,000 years would have ample time to be captured by the performance
assessments. Based on these considerations, the 1 million-year period is a sufficiently long
time frame to evaluate the potential consequences of both gradual processes and disruptive
events on disposal system performance.
In summary, for regulatory policy as well as site-specific scientific considerations, we
believe that fixing the period of geologic stability for compliance assessments at 1 million
years provides a reasonable test for the disposal system performance. We believe a fixed
time period is necessary both to provide a definitive marker for compliance decision-
making and to prevent unbounded speculation surrounding the factors affecting engineered
barrier performance and the ultimate timing of peak dose projections. Examination of site
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characteristics indicates that the influences of natural processes and events on release and
transport of radionuclides would be demonstrated even for waste package failures
occurring relatively late in the period. We believe that setting a 1 million-year limit is a
cautious, but reasonable, approach consistent with the NAS position on bounding
performance assessments for uncertain elements affecting disposal system performance.
Finally, explicitly defining the period during which our standards apply will focus attention
on times for which the geologic setting and associated processes are more quantifiable and
boundable, rather than entering debate on disposal system performance in time periods
where the fundamental geologic regime may have sufficiently changed so that the
"scientific basis for performance assessment is substantially eroded and little useful
information can be developed." (NAS Report p. 72)
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Section 11 Updating the Dose Methodology
Issue A: Agree with the proposal
1.1 support the proposal to use radiation weighting factors and tissue weighting factors
currently recommended by the ICRP to calculate the dosimetric quantity specified in dose
criteria used in the regulations. EPA's justification for this change is technically sound.
(Comment 0186-2)
2.	NARUC agrees with updating the dose measurement methodology to current
internationally agreed protocols as outlined in Section II.C.6. (Comment 0217-8)
3.	We endorse EPA's proposal to use updated dose calculation factors.. .The National
Commission on Radiological Protection (NCRP) has been urging the adoption of the newer
dosimetry for years. The United States currently has no established policy regarding the
updated dose conversion factors. Meanwhile, other nations have either wholly adopted the
ICRP 60/72 approach or are in the process of doing so. The ICRP 26/30 approach is
considered obsolete outside the US. Numerous countries have required the use of the most
recent ICRP guidance in national legislation.. .Therefore, adoption of this methodology
represents a good practice that will support a regulation that is both protective and stable
that will not need to be adjusted in the future absent some major change in basic scientific
understanding. (Comment 0298-23)
4.	We also agree with revisions to the rule to be more current with international scientific
protocols in dose measurement methodology. (Comment 0368.5-3)
Response to Issue A:
We have made some technical changes to the proposed methodology in response to
comments addressed in Issues B and C below, but the same general approach has been
followed.
Section 11 Updating the Dose Methodology
Issue B: EPA has misused the terminology - EDE and ED are not the same
1. As indicated in a previous comment, I support the proposal to update the tissue and
radiation weighting factors used to calculate what EPA refers to as the annual committed
effective dose equivalent. However, it seems silly to me to refer to this quantity as an
"effective dose equivalent," rather than "effective dose," simply because the Energy Policy
Act calls for use of the former quantity rather than the latter. Congress did not make a
conscious choice here. EPA should be aware of two points concerning discussions of this
issue in the Supplementary Information. First, ICRP Publication 26 does not use the term
"effective dose equivalent." Rather, Publication 26 presents an equation to represent this
quantity, but without giving it a name. The name "effective dose equivalent" does not
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appear until Publication 28. What all this means is that the term "effective dose
equivalent" refers only to the tissue weighting factors given in Publication 26. If any of the
weighting factors are changed, the resulting quantity is not "effective dose equivalent. The
second point is that the desire to avoid cumbersome terminology, such as "collective
committed effective dose equivalent," was not the main reason for the ICRP's change to
"effective dose" in Publication 60. The main reason was that the new quantity "effective
dose" is quite different from the effective dose equivalent. Not only are the values of tissue
weighting factors different, but they also have a different basis. Tissue weighting factors in
the effective dose equivalent represent fatal cancers and hereditary effects in the first two
generations only, whereas tissue weighting factors in the effective dose represent a
combination of fatal cancers, non-fatal cancer incidence, length of life lost per fatal health
effect, and hereditary effects in all generations. Thus, a different name clearly was needed
to avoid confusion in communications. (Comment 0186-19)
Response to Issue B:
This comment is technically accurate in most respects, but a closer reading of ICRP 60
supports EPA's interpretation that effective dose equivalent (EDE) and effective dose (ED)
are interchangeable concepts. ICRP defined two weighting factors in ICRP 26, the
radiation quality factor, Q, and the tissue weighting factor, WT. (Docket No. EPA-HQ-
OAR-2005-0083-0425) In ICRP 60, the quality factor was replaced by the radiation
weighting factor, WR. Although defined somewhat differently, the value of WR for alpha,
beta and gamma radiation remained the same as for Q, i.e., 20 for alpha radiation and 1 for
beta and gamma radiation. (Docket No. EPA-HQ-OAR-2005-0083-0421) In ICRP 26, the
tissue weighting factor was presented as a rigid construct with defined values for specific
organs. In ICRP 60, the tissue weighting factor was redefined as a set of recommended
values for an expanded set of organs and it was explained that the attributes of the Wt
include the components of detriment given by this commenter (fatal and non-fatal cancers,
length of life lost, and hereditary effects). However, the ICRP makes a clear distinction
between its renaming of the doubly weighted dose quantity from committed effective dose
equivalent (CEDE) to effective dose (E) and its redefining of Wt. The association of EDE
with the ICRP 26 tissue weighting factors is thus coincidental but not required. The
following paragraphs from ICRP 60 support EPA's interpretation that CEDE and E are
synonymous concepts:
Para. 27: "... The weighted equivalent dose (a doubly weighted absorbed dose) has
previously been called the effective dose equivalent but this name is unnecessarily
cumbersome, especially in more complex combinations such as collective
committed effective dose equivalent. The Commission has now decided to use the
simpler name effective dose, E. The introduction of the name effective dose is
associated with the change to equivalent dose, but has no connection with changes
in the number or magnitude of the tissue weighting factors. ..." [Italics added]
Para. 31: "The values of both the radiation and tissue weighting factors depend on
our current knowledge of radiobiology and may change from time to time. Indeed,
new values are adopted in these recommendations. .. .It is appropriate to treat as
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additive the weighted quantities used by the Commission but assessed at different
times, despite the use of different values of weighting factors. The Commission
does not recommend that any attempt be made to correct earlier values. It is also
appropriate to add values of dose equivalent to equivalent dose and values of
effective dose equivalent to effective dose without any adjustments. ..." [Italics
added]
In summary, EPA believes that the intent of Congress in specifying EDE is that the Yucca
Mountain standards be based on a doubly weighted dose quantity, not that the assessment
of that quantity be tied to old science. EPA uses EDE for consistency with the terminology
used in the legislation, but adopts the current recommended values for Wt. Our approach is
thus fully consistent with current ICRP recommendations.
Section 11 Updating the Dose Methodology
Issue C: EPA has omitted the dose coefficients in ICRP 72 making the proposed
dosimetry update internally inconsistent
1.	The Department recommends that EPA not specify weighting factors, but simply require
that the calculation of doses be consistent with the International Commission on
Radiological Protection (ICRP) 60 and 72 methodologies . The recommendation for the
specific dosimetry system to be used needs to be internally consistent and include both
radiation and tissue weighting factors. (Comment 0352-39)
2.	EPA proposes "... to adopt updated scientific factors for calculating doses to show
compliance with the storage, individual-protection, and human-intrusion standards... "
EPA indicates that it accepts the ICRP 60/72 factors and any factors that may be produced
in the future that are incorporated by EPA into Federal Guidance. EPA then proceeds to
adopt the ICRP 60 radiation- and organ-weighting factors and give their values in EPA's
Appendix A. By referencing ICRP 60 and ICRP 72, EPA gives an impression that it
recommends that the Department use ICRP 60 radiation-weighting factors, organ-
weighting factors, and ICRP 72 dose coefficients (which use radiation- and organ-
weighting factors from ICRP 60). However, in its proposed rule and, in particular,
Appendix A, EPA clearly recommends that only the new radiation and organ weighting
factors be adopted, and makes no specific recommendation regarding the source of dose
coefficients. EPA proposes to adopt the ICRP 60 and 72 radiation- and tissue-weighting
factors and gives their values in EPA's Appendix A... .NRC proposes to modify its rule "to
include a definition for 'weighting factor' that conforms the weighting factors to be used in
dose calculations to the values EPA proposes." In its rule, however, NRC proposes
weighting factors "for an organ or tissue" (Part 63 .2, definition of weighting factor) and
omits the radiation weighting factors that EPA proposes in Table A. 1. (Comment 0352-40)
3.	The set of tissue-weighting factors that EPA proposes in Table A.2 represents the most
current recommendations of ICRP. It is based on recommendations of ICRP 60 with the
addition of the extrathoracic region (ICRP Publication 66) and the clarification of tissue-
weighting factors for colon and upper large intestine (ICRP Publication 69). The potential
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problem is that dose coefficients (i.e., ICRP Publication 72 and Federal Guidance Report
13) consider a different set of organs. The Department, therefore, recommends that EPA
not provide the list of tissues and organs but require that the calculation of doses be
consistent with ICRP 60 and 72 methodologies. (Comment 0352-41)
Response to Issue C:
The comments suggest that the appendix should not include specific weighting
factors, but state only that doses are to be calculated in accordance with the methods of
ICRP 60 and 72. (Docket Nos. EPA-HQ-OAR-2005-0083-0421 and EPA-HQ-OAR-2005-
0083-0427) The commenter believes this is appropriate because NRC's proposed licensing
requirements specified using the tissue weighting factors, but did not mention the radiation
weighting factors. (70 FR 53313, September 8, 2005) Further, the commenter points out
that dose coefficients in ICRP 72 (and Federal Guidance Report 13, Docket No. EPA-HQ-
OAR-2005-0083-0072) address a somewhat different set of organs than do the tissue
weighting factors. We have not adopted the commenter's suggestion because we believe it
could lead to questions regarding the appropriate factors to use. We note that ICRP 60,
unlike ICRP 26, is not tied to a specific set of weighting factors, and allows for the
possibility that users will substitute their own preferred set of factors. Stating only that the
methods of ICRP 60 and 72 be used to calculate dose, without the additional stipulations in
the appendix, would not provide sufficient clarity on this point. Therefore, we are adding
language to the definition of "effective dose equivalent" in § 197.2 to the effect that NRC
can direct that other weighting factors be used to calculate dose, consistent with the
conditions presented in Appendix A. We believe this addresses the commenter's concern.
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Section 12 Ground-water Protection
1.	The proposal abandons any long-term groundwater protection standard. (Comments
0103-2 and 0145-2)
2.	At the time when the public faces the highest risk of radiation exposure, the EPA
proposes easing the overall public health standard and throwing out the groundwater
standard. Groundwater is acknowledged as the primary path of exposure; the time that
exposure is at its greatest is after 10,000 years. (Comment 0111-3)
3.	The ground water protection standard of 4 mrem per year should be extended to the time
of peak dose. (Comments 0130-5, 0133-4, 0134-2, 0135-4, 0137-4, 0144-3, 0146-4, 0147-
4.	0148-4, 0149-3, 0159-4, 0160-3, 0163-4, 0164-3, 0165-2, 0195-6, 0302-16, 0327-3, and
0341-9)
4.	Although EPA will not consider comments on any aspects of groundwater protection
standards in § 197.30 and § 197.31, discussions of those standards in the Supplementary
Information surely must be open to comment	discussions in Section II. A 3 to support
EPA's decision not to extend groundwater protection requirements beyond 10,000 years are
weak on technical grounds. Furthermore, some of EPA's arguments are an affront to
sensibilities of knowledgeable readers. For example, EPA claims that "protection of public
health from releases to ground water over times beyond 10,000 years will be provided by
extending the individual-protection standard to the time of peak dose." This essentially is
an argument that EPA has rejected time and time again when NRC and DOE have used it
to object to EPA's application of drinking water standards as groundwater protection
requirements in regulating waste disposal or cleanup of contaminated sites. (Comment
0186-22)
5.	In its earlier radiation rule for Yucca Mountain, EPA promulgated an independent
groundwater protection standard that limits radiation in groundwater in an attempt to
comply with safe drinking water standards established in the United States. In the proposed
standard, EPA curtailed its groundwater protection after 10,000 years and subjects drinking
and irrigation water in Amargosa Valley to unacceptable, dangerously high levels of
radiation. Only through the abandonment of its responsibility to future generations is EPA
able to forego protection of Nevada's groundwater. (Comment 0209.6-7)
6.	In its earlier Yucca Mountain rule, EPA set a groundwater protection standard that limits
radiation to groundwater available for human use, such as in Amargosa Valley, to levels
required for safe drinking water throughout the country. In a proposed new standard, EPA
ends that protection after 10,000 years leaving drinking and irrigation water with only the
higher, unacceptable dose limit. Nowhere in its regulations or policies, except here, does
EPA put a time limit on protecting the quality of our drinking water resources. And again,
the collusion is obvious as DOE's performance models show Yucca Mountain will greatly
exceed safe drinking water levels for radiation during the period of maximum releases.
(Comment 0209.7-7)
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7.	Moreover, the logic of the Court's opinion, and the NAS recommendation upon which it
is based, clearly indicate that EPA could not readopt the 10,000-year cutoff even if it did
accept comment. The NAS rejected a 10,000-year cutoff because (1) it saw no scientific
basis for drawing lines at 10,000 years; and (2) it realized that a 10,000-year cutoff would
terminate the standards before the time of peak risk. That reasoning is just as applicable to
groundwater protection as it is to individual exposure. The NAS already has concluded that
the physical systems at the site, including all those that influence groundwater flow, are
sufficiently predictable that there is no reason for cutting off compliance assessments at
10,000 years. And it has similarly noted that there is no sense in cutting off compliance
assessments while the risk is just beginning to increase. Indeed, given DOE's assumption
that no releases to groundwater will occur prior to 10,000 years, and EPA's ratification
(through its agreement with DOE's assumptions about container corrosion) of that
assumption, a 10,000-year-only groundwater standard would be nothing more than a public
relations maneuver. For that reason, the NAS's recommendations and the Court's holding
compel extension of the groundwater standard through peak dose. Indeed, the opinion is
devoid of any suggestion that EPA, once it has decided it is necessary to provide a separate
groundwater standard, could then adopt a period of compliance that the Court and NAS had
expressly rejected. (Comment 0226-21)
8.	EPA also fails to articulate any credible ground for terminating the groundwater standard
that can be reconciled with its prior explanations of its groundwater protection policy, or
with its statutory responsibility to promulgate standards protective of public health and
safety.. .To excuse its early termination of groundwater protection, EPA insists in the
proposed rule that public health protection from groundwater releases will be accomplished
by extending the individual protection standard through peak dose. 70 Fed. Reg. at 49024.
But, as discussed above, EPA's post-10,000-year individual protection standard is grossly
inadequate. Application of the proposed 350-millirem (1000-millirem mean equivalent)
standard to protection of public health from releases to groundwater would create the
lowest level of protection, by far, ever proposed by a regulator, and would be contrary to
the Agency's overall pollution prevention policies. EPA's explanation also cannot be
reconciled with its responses to comments addressing earlier challenges to the separate
groundwater standard. As EPA then explained, the individual protection standard is not a
sufficient substitute for groundwater protection. Responses to Comment, 6-11, 6-12. As
EPA counsel orally confirmed during the NEI litigation, EPA's separate groundwater
standard "furthers the statutory goal of protecting public health and safety." January 14,
2004 Transcript at 59. And in NEI, as EPA correctly notes, the Court "concluded that
[EPA's] reasoning for including such a standard as a means to protect the ground-water
resource was sound and consistent with the Agency's overall pollution prevention policies."
70 Fed. Reg. at 49024. (Comment 0226-22)
9.	By proposing to not establish a ground water protection standard after 10,000 years, the
EPA is in violation of the NWPA requirement (above) to ensure that the environment is not
adversely affected for future generations. (Comment 0263-5)
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10.	We urge EPA to adopt instead, a single, uniform protection standard for the entire
projected life of the proposed repository, before and after 10,000 years, of 4 millirem for
the groundwater protection standard. (Comment 0276-2)
11.	The Safe Drinking Water Standard should also extend through this period [the period of
peak risk, which is more like 300,000 years (according to DOE calculations)]. (Comment
0289-4)
12.	The groundwater under Yucca Mountain provides drinking and irrigation water to the
tens of millions of people who live in the Amargosa Valley and Southern California.
(Comment 0293-3)
13.	In its original rule, EPA's groundwater standard was set at 4 millirems per person per
year for 10,000 years. The Court voided this standard. Yet, in its revised proposal, EPA
leaves this standard in place, with no groundwater standard or protections after 10,000
years. (Comment 0293-4)
14.	EPA has correctly concluded that "The Court's decision does not affect the ground-
water protection standards" The court did not rule that EPA was required to promulgate a
groundwater protection standard or that one was in any way necessary for consistency with
the NAS recommendations, but rather that it was within the agency's discretion to decide
whether or not to prescribe such a standard. EPA's proposal to not extend the existing
groundwater protection standard represents an appropriate exercise of that discretion.
(Comment 0298-22)
15.	Under the new EPA proposed rules, it is not only 'permissible' to expose future
generations to far higher doses of radiation than we would tolerate today, but it is also
acceptable to deprive them of clean water. Compliance with the current Safe Drinking
Water Act standard, which limits radiation in drinking water to 4 millirem/year, will only
be required for the first 10,000 years if the rule is approved. In the period beyond 10,000
years, EPA switches to a 350 millirem/year all pathway exposure limit, which means that
much higher levels of radiation could be allowed in drinking water. Water is a precious
resource, especially in arid areas such as Nevada and southeast California, and will require
more protection as time goes on. Yucca's radioactive wastes will likely leak into the
underlying drinking water aquifer, which will become the primary pathway for harmful
doses to people downstream. The Safe Drinking Water Act standard should be applied to
protect Yucca's aquifer and the people downstream for as long as the high-level radioactive
wastes remain hazardous, hundreds of thousands of years into the future. (Comment 0301-
9)
16.	Drinking water standards are based on people not drinking water (for one half of their
daily liquid intake). How insane is that? Do the cows and pistachio trees, the jackrabbits
and creosote brush which we use for anti-cancer medicine, all go to Safeway for Coca-Cola
to drink every afternoon? (Comment 0306-4)
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17.	EPA posits that the Court ruling did not address the ground-water standard compliance
period. The Court vacated the rule premised on a central point: "40 CFR 197 to the extent
that it incorporates a 10,000 year compliance period because, contrary to EnPA section 801
(a), that compliance period is not based upon and consistent with the recommendations of
the NAS." The Court did not separate out the ground-water standard and its attendant
compliance period for special, more lenient treatment in terms of consistency with the NAS
recommendations. Refusal to take comment on the matter runs afoul of the Administrative
Procedures Act to allow for public notice and comment. (Comment 0311.1-13)
18.	In light of DOE's conception that no waste will leak from the containers for the first
10,000 years, the provision of a ground water standard in the first instance is an apparition,
and devoid of any meaning. EPA's concession to the limits of the engineered barriers and
the inherent weakness of the Yucca Mountain geology as a waste isolating system serves to
highlight the absurdity of its draft rule. The performance assessments make it clear that the
two-tiered approach is a mockery of the concept of protective standards by neutralizing the
15mrem/yr standard and the 4 mrem/yr ground-water standard prior to the time they are
most needed, which also avoids their affecting the design of the site or threatening its
viability. (Comment 0311.1-14)
19.	Another casualty of EPA's proposed rule is the Safe Drinking Water Act equivalent
standard limiting radiation in drinking water to 4 mrem/yr, which EPA would only enforce
for the first 10,000 years, but would then replace with the 350 mrem/yr all pathway
exposure limit. Water is a precious resource, especially in and areas such as
Nevada and southeast California - Yucca's watershed — which will require more, not less,
protection as time goes on. Yucca's radioactive wastes will leak into the underlying
drinking water aquifer, which will become the primary pathway for harmful doses to
people downstream. The Safe Drinking Water Act standard should be applied to protect
Yucca's aquifer and the people downstream for as long as the high-level radioactive wastes
remain hazardous, hundreds of thousands of years into the future. The 4 mrem/yr radiation
dose limit for Yucca's underground drinking water supply that EPA currently proposes to
end at 10,000 years should be applied all the way out to peak dose, hundreds
of thousands of years into the future. (Comments 0324-9 and 0324-14)
20.	If, as EPA states on page 49018, column 3, that "There are two major aquifers beneath
Yucca Mountain. Regional ground water in the vicinity of Yucca Mountain is believed to
flow generally in a south-southeasterly direction," then the massively leaking dump would
threaten Ash Meadows National Wildlife Refuge, an internationally recognized gem of
biological diversity just 25 miles or so south/southeast of Yucca Mountain, home to several
species of endangered desert pupfish (such as the Devil's Hole pupfish) found nowhere else
on Earth. This would be in addition to the dangers presented by massively leaking
radioactivity to the Amargosa Valley agricultural community south of Yucca, which
utilizes Yucca's groundwater for drinking water and irrigation water. (Comments 0324-18,
0324-23, and 0324-24)
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21.	If the repository is licensed, a ground water monitoring program should be developed to
evaluate potential impacts in California. In addition, a ground water contamination
mitigation, clean-up and decontamination plan should be developed prior to beginning
waste emplacement in the repository. (Comment 0326-4)
22.	The proposed standards should be revised so that the time frame for the ground water
protection standard is the same as the individual protection standard (at least 1 million
years). However, since the individual protection standard includes the ground water
pathway, the compliance period for both standards (individual protection standard and
ground water standard) should be the same and should include the time period when
maximum risk to the public and environment will occur. EPA should revise the proposed
standards so that the separate ground water standard extends at least to 1 million years, in
order to be consistent with the individual protection standard, and includes the period of
maximum risk to the public and environment. The effect of this change would be to adopt a
more scientifically acceptable and consistent standard to protect public health and the
environment. (Comment 0326-8)
23.	Section I.bb., Page 49020 - The Yucca Mountain site is in an area of numerous faults,
that have had activity as recently at June of 1992 (5.6 magnitude earthquake, 12 miles
southeast of the project site). The rule does not explain how the 10,000-year time frame is
"within the period of geologic stability." Board staff is conceded that the rule terminates at
the end of the 10,000-time period, and does not set any standard on the ease of radiation
beyond the time frame. The rule basically sets a time period to protect water quality, and
after that time period the proposed rule does not provide beneficial use protection. What
problems will arise by setting the standard for a 10,000-year time frame, i.e., what will
happen after 10,000 years? (Comment 0326-9)
24.	Section II.A. 1., Page 49023 - The proposed rule indicates that "Assumptions regarding
the possible uses of ground water are quite speculative and have been avoided to the extent
possible in the setting of the standards." Board staff is concerned that the possible uses of
groundwater have not been addressed in the proposed rule. In a Regional Board letter to the
California Energy Commission (dated January 10, 2000 - see Attachment), Board staff
indicated that groundwater appears to move through the saturated zone from Yucca
Mountain to the accessible environment (i.e. surface springs near the Death Valley region -
20-30 km away) in less than the 10,000-year
regulatory compliance period. Regional Board staff comments on this issue have not been
addressed. (Comment 0326-11)
25.	Inyo County contends that the EPA's radiation protection standards for the proposed
repository are unacceptable, since they would allow for the contamination of those aquifers
that support human populations and federally protected natural habitat in both the
Armargosa Valley and Death Valley National Park. (Comment 0326-13)
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26.	A major concern about these weakened standards is the issue of water	Yucca's
radioactive wastes will leak into the underlying drinking water aquifer, which will become
the primary pathway for harmful doses to people downstream. The Safe Water Drinking
Water Act standard should be applied. (Comment 0349-5)
27.	The actual effect of this rule is that while the 350 millirems per year is '"all pathways,"
the radiation will be in the water... [0]ne of [Yucca Mountain's] major weaknesses is that
the radioactivity could be in the water and would not be diluted so that it could direct effect
humans, unlike radiation leaking into a large river where the effects would be greatly
diluted. EPA has not directly stated that the groundwater standard, which is 4 millirems per
year prior to 10,000 years, will in effect jump to 350 millirems per year due to the nature of
the site. The proposed EPA rule should explain why 4 millirems per year is protective up to
10,000 years, and then 350 millirems per year is protective, from just after 10,000 years to
one million years. (Comments 0353-6 and 0361-6)
28.	EPA chose to abandon its Safe Drinking Water Act standard for drinking water
contamination (4 millirems per year) after 10,000 years. It set the maximum contaminant
level at a dangerously high 350 millirems per year. The rationale which EPA uses to justify
its rejection of drinking water standards is the fact that the Court did not specifically state
that groundwater protection standards must extend beyond 10,000 years. EPA states that
such a decision is solely at its discretion. Yet if the standard is 4 millirems per year for the
first 10,000 years, it logically follows that this standard should continue or become more
stringent during the time of peak risk after 10,000 years. For the health and safety of future
generations, we urge EPA to include a radiation standard for groundwater which conforms
to the standards of the Safe Water Drinking Act. (Comments 0360-5 and 0363-5)
29.	Although radiation standards for groundwater contamination from Yucca Mountain are
relevant to the health and safety of future generations, EPA refuses to consider any
comments on groundwater protection standards. We also request that comments on the
groundwater standard be accepted and considered in the Final Rule. (Comments 0360-6;
0363-6)
30.	What is the groundwater standard for the first 10,000 years and why isn't there one
after that? (Comment 0367.1-13)
31.	What scientific justification is there for limits on radioactivity in water? (Comment
0367.2-2)
32.	Again, we believe you should apply the "Safe Drinking Water Act" throughout if we
imagine that human exposures will be the same whether you're in Nevada in our time or in
future generations. ... we also urge you to enforce a separate ground water protection
standard of less than four millirem per year with a period beyond 10,000 years. (Comment
0368.2-4)
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33.	Incredibly EPA is proposing to arbitrarily abandon its ground water standard after
10,000 years at the point when the ground water will become increasingly contaminated
according to DOE's models. The ground water standard is integral to the protectiveness of
the overall radiation standard and EPA should extend the ground water standard to one
million years and must take into consideration all public comments on this issue.
(Comment 0368.6-5)
34.	EPA has declared that since it is not modifying ground water standards that it does not
have to consider public comment on this vital aspect of the proposed regulation. Simply
because the court decision allows EPA to set a ground water standard does not mean the
agency is exempt from considering public comment on its decision to not extend the
ground water standard to one million years. (Comment 0368.6-6)
35.	The "Safe Drinking Water Act" standard should be applied to protect Yucca's aquifer
and the people downstream for as long as the high-level radioactive waste remains
hazardous which, of course, is hundreds of thousands of years into the future. (Comments
0368.7-3 and 0368.13-6)
36.	Now the EPA proposes a new standard which compounds this problem by doing away
entirely with the water standard after 10,000 years and setting a radiation level that throws
out decades of precedent-setting policy embedded in EPA's drinking water limit of four
millirem, air emission of ten millirem, or Superfund cleanup to three millirem. The "Safe
Drinking Water Act" standard should be applied to protect Yucca's aquifer and the people
downstream for as long as the high-level radioactive wastes remain hazardous hundreds of
thousands of years into the future. (Comment 0368.9-2)
Responses to Section 12:
Several comments expressed the opinion that we should take comment on the ground-water
standard (Comments 0186-22, 0360-6, 0363-6, and 0368.6-6). We did not propose to
extend the compliance period for the ground-water protection standard beyond the 10,000-
year time frame in our 2005 proposed standards and explicitly stated, "We are not
proposing to change any aspect of the ground-water protection standards... .we are not
requesting and will not consider public comment on either the storage standard or ground-
water protection standards." (70 FR 49022, August 22, 2005). Therefore, as these
comments are outside the scope of this rulemaking, we are not responding to them. (We
note, however, that we have addressed legal concerns related to this decision in Section 24
of this document.)
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Section 13 Tribal-related Comments
I.1	ask you to reconsider and stop the recurrent disregard for the sovereignty of the Native
American nation and the sanctity with which they regard this mountain. (Comment 0118-
1)
2. Then there is the question/issue of damage to the First Nations near Yucca Mountain.
Years ago, a stop was put to similar foolishness on First Nation's sacred ground in Nevada.
Now is not the time to overturn those nobler motives. (Comment 0123-2)
3.1 want to protest the Yucca Mountain nuclear waste disposal site since it is a sacred site
to the indigenous people who live in the area. (Comment 0125-1)
4.	The most egregious claim is the assertion that this proposed standard has no tribal
implications. Executive Order 13175 forces the agency to develop a process to receive
input from tribal governments on any potential impact this standard may have. The EPA
arrogantly ignores this order by declaring the proposed rule will have no substantial effects
on one or more tribal governments, or on the relationship between the Federal Government
and Indian tribes. This is absolutely absurd. Yucca Mountain sits on the sacred land of the
Western Shoshone people and WILL adversely affect the indigenous population in
surrounding areas. (Comments 0130-8 and 0195-9)
5.	The Yucca Mountain proposal is unsound and definitely has disastrous "tribal
implications." (Comment 0140-1)
6.1 believe that Native Americans have suffered enough without the dumping of toxic
wastes on their land. (Comment 0162-1)
7.	We believe the proposal to bury 77,000 tons of high-level radioactive waste on
geologically unsuitable, sacred Western Shoshone Indian land at Yucca Mountain, Nevada,
is dangerous and ignores the indigenous people on those lands. (Comment 0164-6)
8.	There should be meetings held in their sovereign territory (Indian territories), especially
on transportation issues. (Comment 0173-2)
9.	Also, another thing that's occurred is the people that have come in from tribes to speak. I
heard several times where you've said, Well, we can have a separate conversation with you
about what's happening. Well, it's their land. I'm also told that they have radiation
standards, and they have good ideas about how to manage the land, and they've never been
spoken to. (Comment 0209.2-2)
10.1 first want to request an additional 30 days to comment on behalf of the tribes. I would,
myself, view that as an act of trust, responsibility exercised by the EPA. And no less is
expected by the tribes, I'm sure, with ties to Yucca Mountain. (Comment 0209.5-1)
II.1	think it's important that the EPA clarifies how it constructs risks so that it's culturally -
- culturally appropriate context for risks, threat, or hazard to the vulnerable population that
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is developed, as well as health communications strategy, to communicate those risks to the
tribes in a way that they understand. I think that right now there's a particular class of
individuals that are being disenfranchised and that is a vulnerable population. (Comment
0209.5-2)
12.	Even though the EPA has spent a lot of time going around in having meetings with us,
it doesn't sound like you did much on the American — the Native-American front. So it
appears that you're going to have to go out to Moapa. You may have to go to Duck Water.
You may have to go to Death Valley. There are tribes and Indian nations here that need to
be a part of this. And as been mentioned before, they need to be a big part of it, and it needs
to be a government-to-government sort of process. And you may as well take the NRC with
you as well because I don't think they've been out there either. And they're now in the
process of revising their regulations too. (Comment 0209.14-3)
13.	Down in the reading a little bit, in the paragraph that says: This proposed rule does not
have tribal implication as specified in executive order. The rule proposals today will
regulate only that DOE owns the land owned by the federal government. The rule proposed
today does not have substantial direct affect on one or more Indian tribes.
Well, I wrote here two words. I strongly disagree with that because in the valley
here, we have Las Vegas Paiute tribe, and close to us, we have Moapa Paiute tribe. And in
this region, Region 9 of the EPA, we have 154 Indian tribes. Some of them close to Death
Valley, some of them north of here. And if we consider the State of Nevada, according to
the law, the Nuclear Waste Policy Act, as affected state, some of these tribes are affected
tribes. (Comment 0210.5-1)
14.	You need to start thinking about having public meeting with the governments of and
the peoples of the Native American tribes. The U.S. government has a trust responsibility.
(Comment 0210.5-2)
15.	I'm from the Las Vegas Paiute tribe... .Nobody knows, like we say, in a million years
what's going to happen. And I know there's a lot of people who have — who are educated
and talk about this and that. But we don't know. I mean, no one knows in 100, 300, 400
years from now what's going to happen. Who knows if we'll all be here? But still, we need
to protect the public plus the ground water that comes through the Test Site. It comes all
the way to Vegas. So we need to make sure that that doesn't — is polluted with radiation.
And just thank you for letting us talk and letting me talk but, please, you know, help us and
make it a better — or make a very good judgment to all of us American people plus the
natives too. (Comment 0210.7-1)
16.	The government is doing what its always done; disregarding the Indians and breaking
treaties. (Comment 0210.8-1)
17.	The most egregious claim set forth by the EPA is their assertion that this proposed
standard has no "tribal implications." Executive Order 13175 forces the agency to develop
a process to receive input from tribal governments on any potential impact this standard
may have. I have personally participated in annual Renewal Ceremonies on Yucca Mt.'s
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western flank for many, many years. Native people continue to use medicinal plants from
the region, to hunt and gather as they have for thousands of years. The EPA ignores Order
13175 by declaring the proposed rule will have no "substantial effects on one or more tribal
governments, or on the relationship between the Federal Government and Indian tribes."
This is absolutely unacceptable. (Comment 0306-13)
18.	EPA also states "This proposed rule does not have tribal implications. . . and does not
have substantial direct effects on one or more Indian tribes, [or] on the relationship between
the Federal. Government and Indian tribes . . .". This is preposterous. Yucca Mountain is
sacred and still used as a ceremonial site by the Western Shoshone Indians, who retain
rights to the land under the Treaty of Ruby Valley signed by the US government in 1863.
The Western Shoshone traditional lifestyle, lived at and near Yucca since time
immemorial, may again return to that area someday. In fact, the Western Shoshone Indian
traditional lifestyle was lived at and near Yucca for thousands and tens of thousands of
years until contact with. European Americans in the late 1800s. Western Shoshone
continued to hunt and gather at and near Yucca until the U .S. military and Atomic Energy
Commission seized the land and established the Nevada nuclear weapons test site in 1951,
just 55 years ago. How old is the "rural/residential" lifestyle near Yucca of which EPA
speaks? 25 years old? The duration of the European American lifestyle as currently lived at
and near Yucca is a mere blip in the history of the Western Shoshone people and their
homeland. The Western Shoshone traditional lifestyle could mean far higher doses than
EPA's "reasonably maximally exposed individual" living a "rural/residential" lifestyle
would be exposed to. That EPA claims its proposal does not significantly impact Native
American tribes clearly reveals its ignorance of the decades-long and extensive
involvement of the Western Shoshone National Council, as well as other -federally
recognized Western Shoshone tribes and bands and other tribes and bands, in. striving to
protect traditional homelands and treaty-recognized lands against radioactive
contamination due to nuclear waste dumping as well as other atomic activities in the Yucca
Mountain area . This is a violation of the U.S. federal government's responsibility to relate
with Native American tribes as sovereign governmental entities, on a government-to-
government basis. (Comment 0324-11)
19.	The EPA also asserts that this standard has no "tribal implications." Executive Order
13175 forces the agency to develop a process to receive input from tribal governments on
any potential impact this standard may have. It appears as though the EPA has arrogantly
ignored this order by declaring that this rule will have no "substantial effects on one or
more tribal governments, or on the relationship between the Federal Government and
Indian tribes." How can you say this when Yucca Mountain sits on the sacred land of the
Western Shoshone people and WILL adversely affect the indigenous population in
surrounding areas? (Comment 0328-8)
20.	It (the standards) puts future generations at risk - especially Native Americans in
Nevada. (Comment 0336-2)
21.	The EPA is endangering our native people as well as all U.S. children for generations.
(Comment 0342-2)
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22.	We would like to thank Betsy Fornash of EPA for responding to our request for
consultation. Because of the lateness of EPA's attempts at consultation, we requested an
extension of time for tribes to register their comments. It is also appreciated that Betsy
Fornash responded by extending the comment period for tribes from November 21 to
December 31, 2005. This is a good faith effort to make up for the lateness of the
consultation process. This now provides the opportunity for actual government-to
government consultation. We hope that in the future EPA will initiate consultation as early
as possible when its actions may effect tribal ancestral territories as well as reservations.
Even though (according to EPA) the proposed radiation standard does not apply to
Executive Order 13175 "Consultation and Coordination with Indian Tribal Governments"),
EPA has now recognized that the more broadly worded EPA Indian Policy should be its
guidance: "The agency, in keeping with the federal trust responsibility, will assure that
tribal concerns and interests are considered whenever EPA's actions and/or decisions may
affect reservation environments." (Comments 0360-1 and 0363-1)
23.	Value Mountain on a spiritual level. (Comment 0367.1-16)
24.	Tribal people nearby Yucca Mountain bear a disproportionate burden for the
radioactivity that comes from the nuclear waste. (Comment 0367.2-18)
25.	The Government does not protect Native Peoples from radiation. They cannot "just
move away." (Comment 0367.2-19)
26.	There should be an additional 30 days for tribal people to consult with EPA - and a
meeting in Elko. (Comment 0367.2-25)
27.	The Federal Register states that this ruling does not affect tribes - which is wrong.
(Comment 0367.2-27)
28.	The comment period needs to be extended for a long time in order to engage tribes who
don't use the science that government uses. (Comment 0367.2-28)
29.	Yucca Mountain is also located on native land, which is a particular concern to many of
our constituents, which belongs to the Western Shoshone by the "Treaty of Ruby Valley."
The Western Shoshone National Council has declared this land a nuclear free zone and has
demanded an end to nuclear testing and the dumping of nuclear waste on their land. We
support the claims of the Western Shoshone to their sovereign land which they hold as
sacred and we believe that the revised radiation standard is a form of environmental racism
that will disproportionately harm the lands and health of the Western Shoshone people.
(Comment 0368.7-2)
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Response to Section 13:
EPA recognizes the importance of government-to-government consultation with Tribes and
the significance of the Tribes as sovereign nations. During the comment period, EPA
believed that it was important to get input from the Tribes in Nevada and nearby States and
contacted more than 20 Tribal governments to discuss the updated standard. At the Tribes'
request, we extended the comment time for the Tribes from November 21 to December 31,
2005.
Comments 0173-2, 0209.2-2, 0209.5-1, 0209.5-2, 0209.14-3, 0210.5-2, 0210.7-1, 0210.8-1,
0360-1, 0363-1, 0367.2-25, and 0367.2-28 are concerned with EPA's interactions with the
Tribes. In response to these comments, EPA held three conference calls in November 2005
with members of Tribal governments. Also, Tribal members testified during public
meetings, and EPA received nearly 30 comments on Tribal matters.
EPA's role at Yucca Mountain is to set the radiation protection standards for the potential
disposal system. Comments 0118-1, 0123-2, 0125-1, 0140-1, 0162-1, and 0164-6 imply
that EPA has the ability to stop the potential siting and operation of Yucca Mountain. That
is not the case. We have no authority to determine whether the Yucca Mountain disposal
system is sited or licensed. The only authority that the Energy Policy Act of 1992 gave us
was to establish radiation protection standards for Yucca Mountain. Siting and licensing
are the responsibility of DOE and NRC.
We understand the concerns that Native Americans have relative to releases from Yucca
Mountain (Comments 0336-2, 0342-2, 0367.2-18, 0367.2-19, and 0368.7-2). However, we
have found no evidence that Native Americans would bear a disproportionate burden of the
potential radiation exposure from releases from Yucca Mountain. EPA has set these
standards to protect human health and the environment, including tribal members. We still
believe what we stated in response to similar comments in our 2001 Response to
Comments document (pp 1-39 to 1-40, Docket No. EPA-HQ-OAR-2005-0083-0043):
"After considering the description of tribal land uses in the area of Yucca
Mountain, EPA has concluded that the rural-residential RMEI is fully
protective of Tribal members and the resources they use for four reasons.
First, the Tribal use of natural springs is apparently occurring in the vicinity
of Ash Meadows. EPA is aware of no other area downgradient from Yucca
Mountain where water discharges in natural springs, with the possible
exception of springs in the more distant Death Valley. These natural springs
are likely fed by the "carbonate" aquifer, which is beneath the "alluvial"
aquifer being used in the town of Amargosa Valley (including at Lathrop
Wells) now, and which will likely be used in the future. DOE has not
resolved the question of whether the carbonate aquifer would be
contaminated by releases from the Yucca Mountain disposal system. The
available data indicate that although it is likely that the alluvial aquifer
would be contaminated by releases from the potential Yucca Mountain
repository, flow is generally upward from the carbonate aquifer into the
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overlying aquifers, suggesting that there is no potential for radionuclides to
move downward into the carbonate system. If downward movement were to
occur, however, radionuclide concentrations would be significantly diluted
in the larger carbonate flow system. As a result, springs fed from the
carbonate aquifer would have lower contamination levels than would wells
at the Lathrop Wells location, which tap aquifers closer to, and more
directly affected by, the source of potential contamination. Thus, Tribal
users of natural springs fed by the carbonate aquifer would experience lower
contamination levels than users of the alluvial aquifer at Lathrop Wells upon
whom the RMEI was based. A more extensive discussion of the aquifer
systems and geology in the Yucca Mountain area may be found in Chapters
7 and 8 of the BID.
"Second, the Tribal use of wildlife and non-irrigated vegetation should not
contribute significantly to total individual dose estimates. Gaseous releases
from the repository are not a significant contributor to individual doses
(NAS Report, p. 59) through inhalation or rainfall, and should contribute
less to contamination of wildlife and non-irrigated vegetation than the use of
contaminated well water for raising crops and animals for food
consumption. We believe our requirement that DOE and NRC base food
ingestion patterns on current patterns for the agricultural area directly
downgradient from the repository is a more conservative requirement.
"Third, the dose incurred by the RMEI is calculated at a location closer to
the disposal system than the Ash Meadows area (approximately 18 km
versus 30 km). The RMEI would receive a higher dose from ground-water
consumption than would an individual at Ash Meadows, even if the
carbonate aquifer could be contaminated by repository releases, for the
reasons mentioned above.
"Fourth, the RMEI is assumed to be a full-time resident continually exposed
to radiation coming from the disposal system. It appears that the Tribal uses
are intermittent and involve resources which are less likely to be
contaminated, resulting in lower doses than those to the RMEI."
In addition to the concerns in Comment 0368.7-2 regarding "disproportionate harm" that is
addressed above, it states that the standards are "a form of environmental racism." EPA
takes environmental justice issues very seriously, and we believe that we have established
these standards impartially and as we were directed by Congress when it specifically
authorized and directed EPA to develop such site-specific standards for Yucca Mountain in
the EnPA.
Comments 0130-8, 195-9, 0210.5-1, 0306-13, 0324-11, 0328-8, and 0367.2-27 take issue
with the statement in the preamble to the proposed standards, "This proposed rule does not
have Tribal implications, as specified in Executive Order 13175. The rule proposed today
would regulate only DOE on land owned by the Federal government. The rule proposed
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today does not have substantial direct effects on one or more Indian Tribes, on the
relationship between the Federal Government and Indian Tribes, or on the distribution of
power and responsibilities between the Federal Government and Indian Tribes." We still
believe that this is true; however, we want to ensure that we fully meet our trust
responsibilities. Therefore, as stated above, we contacted more than 20 Tribal governments
to discuss the proposed standards. Also, at the Tribes' request, we extended the comment
deadline for the Tribes from November 21 to December 31, 2005. We also held three
conference calls in November 2005 with members of Tribal governments. Finally, Tribal
members testified during public meetings, and left us with nearly 30 comments on Tribal
matters.
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Section 14 Public Process, Interactions, And Outreach
1.	Request that the comment period be extended to 180 days in order to allow full public
participation in this process and that additional hearings be held in other parts of the United
States. (Comment 107-1)
2.	EPA is also trying to silence voices of opposition by limiting the comment period. It
took EPA more than a year to put together this proposal, but the agency is giving the public
less than two months to review hundreds of pages of documents and put its concerns on
record. (Comment 0111-4)
3.	The comment period for this proposal must be no less than 180 days. The rule should be
published, and the public should receive notice of the hearing, at least 60 days before the
date of the hearing. We also encourage EPA to hold hearings in Reno and Amargosa
Valley as well as Las Vegas. (Comment 0205-2)
4.	We noted a 60 day comment period. In meetings between Clark County staff and your
staff and public outreach consultants, I understand, a comment period of at least 180 days
was recommended.
The promulgation of an adequate radiation protection standard for the proposed
Yucca Mountain nuclear waste repository is vital to the public health and safety of Nevada
residents and visitors. We believe the radiation standard is a primary factor in assessing the
adequacy of the Department of Energy's license application to the Nuclear Regulatory
Commission. We appreciate the fact that you plan to hold two meetings in Clark County,
and have directed our staff to assist you in finding an appropriate location to facilitate
broad public participation and to promote attendance at your meetings. In addition to
providing that opportunity, it is imperative that sufficient time be provided, to Nevada
stakeholders, including Clark County residents, to have sufficient time to review the
revised standard and prepare meaningful comments. We respectfully request that you grant
an extension of time to respond to the proposed revisions to the standard for a full 180
days. (Comment 0207-1)
5.	Before discussing our preliminary views of EPA's proposal, I'd like to acknowledge EPA
for at least partially honoring our and other's request to extend the originally announced 60-
day public comment period. Although we requested 180 days, the 30-day extension has
resulted in a total of 90 days for public review on this complex proposal. We're
disappointed, however, that the request to hold additional hearings in Northern Nevada or
other parts of the state was denied by EPA. (Comment 0209.7-1)
6.	When your staff and public relations firm met with us as stakeholders, I believe we made
it clear that, above all, this was to be a very open process. You can imagine our surprise
when the rules of the game were published, and the process was far from open. I chose to
play by your rules this evening.
In representing the citizens of the state, I tested your process. I have yet to see any
advertisements in the paper. I heard no PSA's, either on the radio or television, but I did see
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a reported story that, indeed, there was going to be a hearing. And I believe the Sierra Club
mailed out 5,000 postcards to let people know that this was happening tonight.
That's not something that's in my budget. Your budget is far greater than mine, and
I believe that job of informing the public is your job, not mine. (Comment 0209.13-1)
7.	I've looked at the draft. I've read it carefully. And I've listened to you two nights' worth
of the roundtables. And what I see and hear are people who are here to defend what they've
done. We started out a long time ago with the DOE talking about the DAD syndrome, D-A-
D. Decide, announce, and defend.
There is a lot more of defense of what you've done than any sort of willingness to
hear, it appears. And that's why I ask that your answers be as short as the questions that
were asked. Because we hear a lot of people defending what they've done, and we don't see
any of what we're putting in being reflected in your final standard. (Comment 0209.14-1)
8.	Finish reading the Napa document. It's full of — read the synthesis, Reference 3, which
you mentioned. It's all process, openness, legitimacy. But you never touched those. You
quote them, but you don't do it, you don't give us an open process. And you haven't done
one in regard to the making of this rule. (Comment 0209.16-3)
9.	The public needs surety that EPA fully understands the health and environmental
consequences of exposure to various levels of radiation. The proposed public health and
environmental radiation protection standards for Yucca Mountain, Nevada, which are
subject to Docket ID OAR-2005-0083 serve to confuse rather than reassure the public.
(Comment 0211.1 -8)
10.	[Congresswoman Berkley] was among those who had requested that EPA add this third
day of hearings in Las Vegas to allow as many people as possible to attend. So we thank
EPA. She thanks EPA for making that possible and is glad that we had this additional day
to talk about this important subject. (Comment 0211.8-1)
11.	Objections to the short public comment time. Nevada proposed 180 days to fully
comment on very complex proposal. No reason was given by EPA not to extend.
(Comment 0226-71)
12.	Citizen Alert sees the methods and actions of the EPA regarding the public as insulting
and inadequate. Offering a meer 60 days for public comments is ridiculous for a standard
of such importance and impact. While we appreciate the extension to 90 days, the comment
period should have been at least 120 days, and there should have been public hearings
across Nevada. Many other communities outside of Nevada also have a stake in the Yucca
Mountain project and we feel that the EPA was also remiss in not having any hearings
outside of Nevada other than in Washington DC. (Comment 0268-9)
13.	EPA's 90 day public comment period is objectionably short, given the million years of
consequences it portends. NIRS, as well as many other public interest and environmental
organizations and concerned citizens, requested a much longer public comment period,
such as 180 days, but were rebuffed by EPA. We also requested additional hearings across
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the U .S., especially considering the broad precedent EPA's revisions could set, for future
repositories in addition to Yucca, as well as, for other radioactively contaminated or even
non-radioactively but toxic chemical contaminated sites across the country. Again, EPA
rebuffed our modest requests. We protest EPA's disinterest in providing more widespread,
reasonable, and accessible public comment opportunities for such a significant proposed
regulation.
It has also been objectionable that EPA has met behind closed doors with the likes
of DOE and NRC beginning very shortly after the July 9, 2004 court decision striking
down EPA's original Yucca regulations. Such secretive meetings violate transparency and
democratic principles, and leave the concerned public with the unmistakable impression
that the federal agencies are conspiring to "cook the books" on the Yucca Mountain Project
and its regulations. (Comment 0324-1)
14.	EPA's public accessibility under this rulemaking has not always been as advertised. For
example, the toll-free information line advertised on page 49016, column 2 of the Federal
Register Notice, contained no message — thus, was not operating, on October 3rd, 2005 -
the very time frame when most needed, given the hearings taken place in Nevada that
week, and the hearing to be held in Washington, D.C. just one week later. (Comment 0324-
16)
15.	Eureka County attended the public meeting and hearing that EPA held in Las Vegas on
October 4, 2005, and participated in the roundtable discussion with EPA officials. We
appreciate that the agency extended the public comment period by 30 days, and note that
the longer 180 day comment period requested by the State of. Nevada would have been
more appropriate given the complexity of the regulations and their long term effects.
(Comments 0353-1 and 0361-1)
Response to Section 14:
EPA has conducted a full, open and appropriate process in this rulemaking, and has placed
all relevant information in the docket (EPA-HQ-OAR-2005-0083), including the scientific
justification for the rule, and taken many actions to notify and involve the public. In
response to comments, we lengthened the comment period for the general public. Given
the narrow focus of the rulemaking, we did not believe that it was necessary to extend the
comment period to 180 days, but we did extend it to 90 days. Similarly, with the narrow
focus of the rulemaking, we did not believe there was a need to issue an advanced notice of
proposed rulemaking.
Both before and after the proposal, we met with a wide range of stakeholders as we
routinely do when developing rules. We met with Federal agencies, including NRC and
DOE, industry and environmental groups, the State of Nevada, and affected counties in
Nevada and California to share basic information about the development of the standards
and to make sure we were taking into account the full range of views, concerns, and
technical issues. Some meetings with Federal agencies were necessary. For example, the
Federal government as a whole had to decide whether to appeal the lawsuit ruling. We
coordinated with NRC as a fellow regulator and, in accordance with Executive Order
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12866, the Office of Management and Budget (OMB) of the Executive Office of the
President reviews significant rules proposed to be promulgated by Federal agencies. The
OMB's role is to coordinate the agencies' budget and policy bases, so we met with DOE
and NRC as part of OMB's process. We also met with DOE, as we often do with regulated
parties in rulemaking to understand technical issues and views. Our reasoning and all data
supporting our proposed approach are public information and in Docket Number EPA-HQ-
OAR-2005-0083.We notified the public of the hearings by advertising in Nevada
newspapers, placing a notice in the Federal Register (70 FR 54325, September 14, 2005),
putting an announcement on our toll-free information line (800-331-9477), distributing an
announcement via our listserv, and posting an announcement on our Web
site(http://www.epa.gov/radiation/vucca/up-to-date). The hearings were held on October 3,
2005 in Amargosa Valley, Nevada; October 4-6, 2005 in Las Vegas, Nevada (the session
on October 6 was added at the request of the public); and October 11, 2005 in Washington
D.C. Fifty-three people testified at the hearings. We did not hold hearings in other parts of
Nevada or in other parts of the country. To ensure that as many citizens as possible had the
opportunity to comment, we provided many avenues to submit comments. Connected with
the hearings we held public information sessions in each location where people could speak
with EPA personnel and ask questions informally; they could also leave hand- or computer-
written comments or comments on a tape recorder. In Amargosa Valley and Las Vegas,
there were also roundtable discussions where anyone could participate in a facilitated
conversation with EPA staff to discuss the standards and allow opportunities for the public
to ask questions of EPA staff, and for EPA to respond. A summary of key points and
questions was recorded for the record.
Overall, we received about 2550 sets of comments that amounted to about 3000 pages of
comments and 1100 pages of attachments. Comments were from a wide range of
individuals and organizations: Nevada Congressional members; the Nevada Governor's
office; counties; tribal governments; the States of Maine, Vermont, and California; nuclear
industry groups; environmental and public interest groups; and DOE. There were many
methods for people to submit comments in writing: electronically, via surface mail, by fax,
courier or personally. Specific instructions and addresses were contained in the proposed
rule and on EPA's Yucca Mountain web site at www.epa.gov/radiation/vucca. We
reviewed all comments and considered them as we developed the final rule.
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Section 15 EPA's Role and Responsibility
1.	EPA "plays God" here as if you have the right to decide what doses future generations
should be allowed to be exposed to. This is wrong. (Comment 0113-5)
2.	It is the responsibility of EPA to promulgate a standard that assures that deadly high-
level radioactive waste is truly isolated from the human and natural environment.
(Comment 0209.6-9)
3.	And I would just finish by saying that the EPA's job is not to worry about the
performance of the repository, not to worry about DOE's uncertainty, not to worry about
DOE's burden of getting a license. Your job is to protect the public health and safety. If
Yucca Mountain doesn't make it, that doesn't make any difference to you. Your job is to do
your job and to protect the public. (Comment 0209.14-7)
4.	It is our hope that you re-examine this decision, focus on fulfilling your obligations of
protecting public safety, and ignore the pressures of rubber-stamping this project. Is it too
much to ask that you implement a rule that will protect the people of Nevada and of this
great nation today and tomorrow? (Comment 0209.15-3)
5.	EPA fails in its most basic mission of protecting human helath and safety and instead
proposes to delegate this ahtority to NRC. (Comment 0275-5)
6.	Citizen Alert is alarmed that the EPA would propose a radiation protection standard,
which clearly reverses the path and ideals of environmental protection established over the
past 35 years. We encourage you to revisit the reason for the creation of the EPA and its
mission to the citizens of the United States. "The mission of the Environmental Protection
Agency is to protect human health and the environment. Since 1970, EPA has been
working for a cleaner, healthier environment for the American people."
http://www.epa.gOv/epahome/aboutepa.htm#history (Comment 0289-1)
7.	It is not EPA's job and, in fact, is a violation of its statutory obligation and its public
responsibility to create a standard that simply accommodates an unsafe site. Instead of
joining the "save the dump" political effort, EPA must abandon this proposal and release a
new draft for comment that provides real protection for public health and the environment
for the dangerous lifetime of the waste. (Comment 0294-6)
8.	EPA should only have burden to what is safe. (Comment 0367.1-21)
9.	It is not EPA's job to ensure that Yucca Mountain can get licensed by the Nuclear
Regulatory Commission. It is EPA's job to set a standard that will be protective of public
health for all generations into the future. (Comment 0368.6-8)
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Response to Section 15:
EPA's role relative to Yucca Mountain was established by the Energy Policy Act of 1992
(EnPA) and is consistent with EPA's overall mission. In the EnPA, Congress directed EPA
to develop site-specific radiation protection standards for Yucca Mountain to protect public
health and safety. Our final standards meet that mandate. The Department of Energy will
be authorized to construct and operate the facility at Yucca Mountain only if it
demonstrates to the Nuclear Regulatory Commission (NRC) that the disposal system will
comply with EPA's radiological protection standards. EPA has not promulgated a standard
with the intention of faciliting a positive licensing decision by the NRC.
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Section 16 FEPs and Screening Criteria
Issue A: General comments
1.	Accordingly, both Lincoln County and White Pine Counties are particularly concerned
with features, events, and processes which might result in unanticipated atmospheric
releases of radiation and exposure consequences for residents living downwind of the
Yucca Mountain site. Review by both counties of EPA's proposed radiation standards for
Yucca Mountain has been focused largely upon the adequacy of EPA proposed multiple-
dose standards regarding protection of public health and the implication of said standards
with regard to how EPA's standards will affect the way the Department of Energy conducts
performance assessments relating to seismic and igneous FEPs. (Comment 0211.1-1)
2.	While some elements of the proposed rule might have been more appropriately left to the
discretion of the Nuclear Regulatory Commission ("NRC"), NARUC agrees with those
sections which cover seismic, volcanic, climactic and general corrosion features, events
and processes (FEP's), as well as the 10"8probability threshold set for very unlikely FEP's.
(Comment 0217-2)
3.	In its proposed rule, EPA has taken an active role in defining the FEPs that DOE must
model. EPA proposes that DOE exclude numerous adverse scenarios from the modeling
process, sometimes without specifying what those scenarios are or delineating the standard
being used to exclude them. An entirely sensible initial EPA proposal that NRC would
have authority to add additional FEPs for the 10,000-year period was unaccountably
deleted (apparently at DOE's insistence), and replaced by a series of artificial and
unfounded limitations that can have no purpose other than to make it easier for DOE to
comply. (Comment 0226-73)
4.	EPA repeatedly cites a perceived need to avoid uncertainties and over-conservatism as a
reason for limiting the FEP-setting process. EPA posits that including all possible
scenarios, even if highly unlikely, would prejudice the analysis towards excessive
pessimism. Indeed, EPA even claims that its decision to include only scenarios that have at
least a 1-in-10,000 chance of occurring over the 10,000 period, and that are likely to have
"significant effects" (a term EPA never defines) is "extremely conservative." 70 FR 49049.
But NAS's conclusions were to the contrary. Describing the basic approach involved in
performing a probabilistic risk analysis, NAS wrote: [t]]o judge compliance against a risk-
based standard of the type proposed, a risk analysis including treatment of all scenarios that
might lead to releases from the repository and to radiation exposures is, in principle,
required. To include them in a standard risk analysis, all these scenarios need to be
quantified with respect to the probabilities of scenario occurrence and the probability of
their consequences to humans, such as health effects of radiation doses. NAS Report at 72
(italics in original; bold text added). In other words, NAS recommended including a broad
range of scenarios and accounting for the remoteness of the more unlikely scenarios by
multiplying a scenario's impacts by its low probability of occurrence. Nothing in this
passage, or anywhere else in the NAS report, suggests that such an approach would be
excessively conservative. (Comment 0226-75)
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5.	A simplified mathematical example indicates why the NAS was correct that an inclusive
analysis is, "in principle," appropriate rather than over-conservative, and why EPA's FEP
approach is inherently unrealistic and optimistic. Suppose that events A, B, C, D, and E
have probabilities of occurrence of 1%, 3%, 7%, 10%, and 12%, respectively, over the next
year. Next, suppose that each event has a likelihood of producing 10 units of exposure if it
occurs. The probable degree of exposures per year thus would be ((probability of A)
(exposures per occurrence of A) + (probability of B) (exposures per occurrence of B).... +
(probability of E) (exposures per occurrence of E). Plugging the overall numbers into the
equation produces an expectation of 3.3 units of exposure per year. There is nothing
inherently conservative about this prediction; the inclusion of "unlikely" events A and B is
compensated by discounting their effect by their likelihood of occurrence. The inclusion of
unlikely scenarios thus does not bias the analysis because the unlikelihood of those
scenarios is accounted for mathematically. (Comment 0226-76)
6.	Now suppose, however, that the regulator has attempted to simplify the modeling by
excluding from consideration all events with a less-than-5% chance of occurring. The
modeler would then not consider events A and B at all—even though they do have a real-
world possibility of occurrence—and would produce a prediction of 2.9 units of exposure
per year. Although the change is not huge, defining FEPs to exclude certain scenarios has
skewed the prediction toward excessive optimism. And the skewing will increase if, as
EPA proposes, probable events with slight effects—for example, an event F which has a
probability of 40% but a likely impact of only one unit of exposure—also are excluded
(Comment 0226-77)
7.	This example illustrates the fallacy of EPA's assertion that its prescribed FEP approach
corrects supposed over-conservatism. In fact, unless compensating mechanisms are
introduced, every exclusion of scenarios decreases the realism of the calculation, and
skews the result toward optimism. The NAS report provides no support for such skewing,
and instead endorses a methodology that provides more realism than that selected by EPA.
(Comment 0226-78)
8.	The NAS report recommends that, in principle, "all" scenarios should be addressed that
"might lead to releases from the repository and radiation exposure." NAS Report at 72.
Nevada understands that direction not to prescribe an infinite number of runs, but to ensure
that EPA's methodology fully accounts for potential releases from the repository and
radiation exposure. This NAS recommendation reflects EnPA's underlying statutory
mandate for EPA to develop standards for the protection of the public health and safety. As
noted below, key exclusions proposed by EPA appear to be inconsistent with the NAS-
recommended approach. (Comment 0226-79)
9.	EPA has excluded a series of events—many of them entirely unspecified—on the mostly
unexplained rationale that their effects would be "insignificant." For example, EPA
suggests that if criticality events are not addressed during the first 10,000 years (which
DOE had proposed it would not do because it assumes that such failure is unlikely), they
also need not be addressed in the post-10,000 year period because, oddly enough, criticality
events at such later times would likely have lesser effects than the earlier criticality events
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EPA already has excused DOE from analyzing. 70 FR 49051 (stating, without explanation,
that "we do not believe such scenarios are either very likely or very important to
performance"). As a consequence, EPA's proposed rule would completely excuse DOE
from analyzing one of the most worrisome threats posed by the repository, at the very time
when waste packages will begin to fail, emptying their fissile contents into pools and piles
of unknown (but perhaps critical) geometries. EPA has also excluded engineering failures,
such as localized corrosion, on the theory that their post-10,000 year effects would be
insignificant. Id. Similarly, EPA apparently acquiesces in DOE's assumption that no
manufacturing defects will exist, without ever considering whether this assumption is
reasonable, let alone sufficiently certain to totally exclude such scenarios from analysis.
Indeed, EPA never defines what its standard of significance is, or itemizes all of the FEPs
that are being excluded, with the consequence that the rule never explains what events are
being left out or how important they might actually be. (Comment 0226-80)
10.	On similar grounds, EPA has excluded from consideration several other FEPs on the
rationale that their effects will be, in EPA's words, "overwhelmed" by the influence of
more important variables. 70 FR 49053; see id. at 49054. Again, EPA is inconsistent at best
in defining what FEPs are being excluded on these grounds; while some, like seismic
effects on hydrology, are specified, others are left unnamed. (Comment 0226-81)
11.	Moreover, EPA never addresses the possibility that the comparatively minor FEPs'
effects would occur in addition to those ostensibly more important ones represented in the
scenarios that will be considered, and thus does not consider that this exclusion may well
understate direct and cumulative effects. This approach is as irrational as a business
declining to account for its smaller expenses on the rationale that they are "overwhelmed"
by the larger ones. In reality, all of the expenses, large and small, influence the bottom line,
and a failure to account for the small ones leave any budget projection overly optimistic.
(Comment 0226-82)
12.	EPA excludes from consideration FEPs that might be increasingly significant with the
passage of time. Some FEPs, like general corrosion, may be of lesser importance during the
first 10,000 years if DOE's sanguine predictions are realized, but could become
increasingly important in the post-10,000 year period. EPA acknowledges this risk with
general corrosion, and requires it to be addressed, but dismisses all other such time-
sensitive effects (without even beginning to specify what they are) on the conclusory
rationale that "the relevant FEPs are already captured within the 10,000 year screening
process, and that any others would be overshadowed by other aspects of the longer-term
modeling." 70 Fed. Reg. at 49055. As a consequence, EPA's rule proposes considering only
the limited subset of FEPs that EPA believes, for largely unspecified reasons, to be worth
modeling. Even if EPA was correct, and the FEPs DOE will consider turn out to be the
most important ones, the collective impact of all the excluded FEPs could have a
significant impact on the performance assessment. By categorically excluding those effects
from consideration, EPA has departed from the NAS recommendation and introduced a
potentially significant level of over-optimism into the assessment. (Comment 0226-83)
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13.	Those exclusions also exceed EPA's expertise. It would be one thing if EPA's cavalier
exclusion of potentially key technical issues were in an area for which the agency has
known and Congressionally delegated expertise, such as the health effects of radiation. It is
another altogether when the issues concern metallurgy, nuclear physics, seismicity, and
climatology. (Comment 0226-84)
14.	The EPA proposal discusses screening out FEPs by probability and consequence within
10,000 years. To provide a realistic prediction of performance after 10,000 year EPA must
consider all FEPs that provide significant consequences over the regulatory period of a
million years. To protect future individuals in the Amargosa Valley, the EPA cannot limit
consideration to only those FEPs that provide a consequence within 10,000 years.
Furthermore the attempted screening of FEPs on independent probability and consequence
arguments is totally fallacious. Screening for probabilistic risk analysis must be done on the
product of these two factors (i.e., probability of occurrence multiplied by the consequence
of the occurrence); otherwise important and possibly dominant contributors to annual dose
can be erroneously excluded with the subsequent falsely optimistic estimate of
performance. EPA must propose and then mandate an approach that correctly takes risk
into account. (Comment 0263-16)
15.	We agree with EPA's decision to limit consideration of FEP's after 10,000 years to
those already required to be considered in the first 10,000 years. (Comment 0298-18)
16.	EPA has overlooked important dynamics in the features, events, and processes (FEPs)
and "reasonable expectations" approach. FEP occurrences that have been screened out or
underestimated could very well increase rates of radionuclide exposure and contamination.
Moreover, significant linkages to climate change, many which are not fully understood, are
wholly ignored in this proposal. (Comment 0312.1)
17.	White Pine County is concerned with features, events and processes (FEPs) which
might result in unanticipated atmospheric releases of radiation and exposure consequences
for residents living downwind of the Yucca Mountain site. Review by the County of EPA's
proposed radiation standards for Yucca Mountain has been focused largely upon the
adequacy of EPA's proposed multiple dose standards regarding protection of public health
and the implications of said standards with regard to how EPA's proposed standards will
affect the way the Department of Energy (DOE) conducts performance assessments
relating to seismic and igneous FEPs. (Comment 0315-1)
18.	Attachments A and B below are included to show that very real problems already exist
with dry cask systems in, the U.S., so EPA cannot assume that there will be no design or
manufacturing problems with waste burial casks at Yucca, as it attempts to do in its
proposed rule. Under its FEPs section (Frequencies, Events, Processes), EPA seems to
agree with DOE's highly unrealistic assumption that no manufacturing defects will exist in
Yucca waste burial containers. This flies in the face of over 20 years of U.S. experience
with dry cask storage, which has seen all too many instances of cask design,
manufacturing, and operational problems. (Comment 0324-33)
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19.	Section 197.12: In order for EPA, NRC, or DOE to assess with reasonable accuracy all
"features, events, and processes" that might affect the Yucca Mountain geological
repository, the probabilities of human intrusion and consequences (e.g., compromised
waste containers and radioactive releases) would have to be included in the analysis. If
human intrusion is properly analyzed elsewhere in the requirements, it should be
incorporated with naturally occurring events (e g., geological or climatological) that could
compromise the repository performance in order to determine the likely performance.
(Comment 0331-10)
20.	The Department agrees with EPA's proposal regarding the treatment of features, events,
and processes and supports EPA's approach to limit the inclusion of highly speculative
features, events, and processes in the calculation of peak dose by defining the treatment of
those specific processes to be included in the calculation. EPA's proposed approach for the
treatment of features, events, and processes is a sound policy decision that avoids
intractable speculation aimed at identifying all conceivable features, events, and processes
that might possibly have an impact in a one million-year compliance period. The
Department agrees that the probability cutoff for features, events, and processes should be
the same as the cutoff originally established in Part 197 for the 10,000-year period, one
chance in 100 million per year. The Department agrees with EPA's proposal that FEPs and
scenarios not included in the 10,000-year analysis need not be considered in peak dose
calculations. The Department agrees with EPA's proposal "that scenarios involving climate
change, seismic activity, igneous activity, and general corrosion should be explicitly
considered in the peak dose calculations".. .The Department interprets EPA's proposed rule
to mean that, with the exception of those specified processes, the calculation of peak dose
will be based on the 10,000-year compliance demonstration. (Comment 0352-9)
21.	The process of general corrosion of the waste packages in the evaluation of
performance to time of peak dose is different in nature from the three natural system
processes recommended by the Committee for inclusion in the evaluation of performance
to time of peak dose (i e., climate change, seismic activity and igneous activity). This
difference should be recognized. EPA should add the following sentence to 197.36(c)(3):
The only subsidiary effects of general corrosion that need be considered are those that were
previously considered in the TSPA for the 10,000-year period (that is, those features,
events, and processes that would not affect 10,000-year performance need not be
considered further).. .There are specific limitations specified in section 197(c) for the first
three of these analyses to ensure that the limitations of section 197.36(a) are applied
properly such that unnecessarily detailed analyses of non-important features, events, and
processes are not required for the peak dose analysis. A similar limitation should be applied
to the corrosion analysis. (Comment 0352-10)
22.	Extending the regulatory period to the time of peak dose has the potential to introduce
arbitrary and unbounded speculation into the assessment of repository performance.. EPA
has prudently rejected the argument that a 100-fold increase in the time horizon for the
performance assessment should be accompanied by a 100-fold reduction in the annual
probability cutoff for the features, events, and processes to be considered in that
assessment. Such a reduction in the screening threshold would require an attempt to
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identify features, events, and processes of an inconceivably low probability, one chance in
10 billion per year, a level associated with literally end-of-the-world events. Making the
compliance determination dependent on unbounded, and perhaps unboundable, speculation
about events of an inconceivably low probability of occurrence theoretically would, at best,
be placing the interests of distant future generations above society today and its
descendants over the next 10,000 years. The one-chance-in- 100-million cutoff itself is
already extremely conservative, approaching the probability of a collision with an asteroid
of the size associated with a major extinction event, or about 1/100 the annual probability
of being struck by lightning. For perspective, the recent draft recommendations of the
International Commission on Radiation Protection express skepticism about estimates of
annual probabilities much below one chance in one million. (Comment 0352-11)
23.	Explicit policy judgments are required to address extremely slow processes that should
be excluded from 10,000-year performance assessments but that could affect the timing
(and potentially the magnitude) of the peak dose.. .Physical-chemical processes that are not
observable without accelerated testing should be excluded from the peak dose assessment.
In the absence of direct observation of such phenomena, it is not possible to develop
reasonable conceptual models of these phenomena or the parameters that describe them;
nor is it possible to develop even cautious bounds on the uncertainty in the parameters.
Because these long-term transient processes are unquantifiable, it is speculative to include
them in any assessments of long-term performance. Undue speculation as to the
appropriateness of a particular long-term transient conceptual model and the uncertainty in
that model would not increase the ability of the regulator and the public to evaluate the
ability of the Yucca Mountain repository to comply with the peak dose level of protection.
Long-term calculation of peak dose should be consistent with and based upon the
processes, conceptual models, numerical models, model parameters and boundary
conditions included in the 10,000-year compliance evaluation. The calculation should not
include unwarranted speculation about slow transient processes.. .This allows a more direct
and representative comparison of the predicted dose to the target and avoids inappropriate
speculation about unknown and uncertain rates of these transient processes. (Comment
0352-12)
24.	The Department has identified FEPs that could potentially affect repository
performance. The identification of these FEPs was not based on any compliance timeframe.
These FEPs were then evaluated for inclusion in an assessment of repository performance
over a 10,000-year period. The Department has subsequently re-evaluated the FEPs over
the period beyond 10,000 years.. .The results of this evaluation support EPA's position
"that FEPs and scenarios not included in the 10,000-year analysis because of limited
consequence during that period need not be considered in peak dose calculations." This
analysis indicates that the bases for excluding most of the FEPs are time invariant... some
processes, such as erosion, are time dependent. However, these gradual and continuing
processes will not have a significant effect on the projection of repository performance over
the period beyond 10,000 years. (Comment 0352-13)
25.	The Department agrees with EPA's proposal that the effects of seismic activity should
be evaluated throughout the one million-year period but limited to those effects resulting in
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damage to the engineered barrier system. FEPs that pertain to the effects of seismic activity
on the Yucca Mountain repository natural barrier system have been excluded over a
10,000-year period based on low consequence. The justifications for excluding these FEPs
for 10,000 years are also applicable to the period beyond 10,000 years because they do not
depend on any time scale. It is, therefore, not appropriate to consider the effects of seismic
activity beyond those that result in damage to the engineered barrier system. (Comment
0352-14)
26. The Environmental Protection Agency's ("EPA's) August 22, 2005 proposed
amendments to 10 C.F.R. Part 197, "Public Health and Environmental Radiation Standards
for Yucca Mountain, Nevada," include provisions at proposed section 197.36 designed to
limit consideration of certain physical processes in the repository system safety
performance assessment in the post-10,000 year performance period. These include a limit
on the Nuclear Regulatory Commission's ability to take account of localized corrosion of
the waste package. This limit is based on an EPA finding that the phenomena of localized
corrosion of the waste packages at Yucca Mountain is sufficiently understood scientifically
that the potential for significant new effects on public safety after 10,000 years should be
ignored. In the proposed amendment EPA concludes these effects must be ignored unless
they can be shown to be significant before then, which EPA seems to think is unlikely. See
70 Fed. Reg. 49053.
In its overly confident conclusions about localized corrosion processes, EPA is at
odds with the experts in the field. In a December 30, 2005 letter to the Congress, the
Nuclear Waste Technical Review Board advised that it "continues to be concerned about
the potential for localized corrosion in deliquescent brines formed at temperatures between
160 C and 220 C from airborne dust that will be deposited on the surface of the waste
packages." Further, in an October 6, 2005 scientific report (not released until late
December), the Nuclear Regulatory Commission's Center for Nuclear Waste Regulatory
Analysis concluded that "under a limited range of conditions, stress corrosion cracking of
Alloy-22 has been observed in environments containing chloride and bicarbonate, which
may be present in water entering the emplacement drifts."
It is clear from these sources, whose technical expertise on waste package corrosion
far exceeds the EPA's, that the science of localized corrosion of the Yucca Mountain waste
packages is still being developed, that significant technical concerns remain, and that more
scientific work needs to be done before the matter can be resolved. Moreover, recent DOE
initiatives to reexamine the waste package design for Yucca Mountain raise serious
questions whether EPA's assumptions about the nature of the waste package subject to
corrosion will comport with reality.
Given this, it is completely arbitrary for the Agency to issue a binding rule that
limits the Commission ability to consider the matter. The licensing and regulatory process
for Yucca Mountain must be based on sound science, but it cannot be if the Agency tells
the Commission that it must willfully blind itself to significant new scientific information.
The recent dramatic changes in DOE's program to develop Yucca Mountain also strongly
counsels against an inflexible EPA rule that treats the Yucca Mountain Project as if it were
frozen in the mid-2005 time frame. (Comment 0362.1-1)
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27.	The Environmental Protection Agency's ("EPA's") August 22, 2005 proposed
amendments to 10 C.F.R. Part 197, "Public Health and Environmental Radiation Standards
for Yucca Mountain Yucca, Nevada" include provisions at proposed section 197.36
designed to limit consideration of certain physical processes in the repository system safety
performance assessment in the post-10,000 year performance period. These include a limit
on the Nuclear Regulatory Commission's ability to take account of localized corrosion of
the waste package. This limit is based on an EPA finding that the phenomena of localized
corrosion of the waste packages at Yucca Mountain is sufficiently understood scientifically
that the potential for significant new effects on public safety after 10,000 years should be
ignored. In the proposed amendment EPA concludes these effects must be ignored unless
they can be shown to be significant before then, which EPA seems to think is unlikely. See
70 Fed. Reg. 49053.
In its overly confident conclusions about localized corrosion processes, EPA is at
odds with the experts in the field. In a December 30, 2005 letter to the Congress, the
Nuclear Waste Technical Review Board advised that it "continues to be concerned about
the potential for localized corrosion in deliquescent brines formed at temperatures between
160 C and 220 C from airborne dust that will be deposited on the surface of the waste
packages." Further, in an October 6, 2005 scientific report (not release until late
December), the Nuclear Regulatory commission's Center for Nuclear Waste Regulatory
Analysis concluded that "under a limited range of conditions, stress corrosion cracking of
Alloy-22 has been observed in environments containing chloride and bicarbonate, which
may be present in water entering the emplacement drifts."
It is clear from these sources, whose technical expertise on waste package corrosion
far exceeds the EPA's, that the science of localized corrosion of the Yucca Mountain waste
packages is still being developed, that significant technical concerns remain, and that more
scientific work needs to be done before the matter can be resolved. Moreover, recent DOE
initiatives to re-examine the waste package design for Yucca Mountain raise serious
questions whether EPA's assumptions about the nature of the waste package subject to
corrosion will comport with reality.
Given this, it is completely arbitrary for the Agency to issue a binding rule that
limits the Commission ability to consider the matter. The licensing and regulatory process
for Yucca Mountain must be based on sound science, but it cannot be if the Agency tells
the Commission that it must willfully blind itself to significant new scientific information.
The recent dramatic changes in DOE's program to develop Yucca Mountain also strongly
counsels against an inflexible EPA rule that treats the Yucca Mountain Project as if it were
frozen in the mid-2005 time frame. (Comment 0365-1)
28.	We agree with the sections of seismic, volcanic, climatic and general corrosion
features, events, and processes, although we think the detailed requirements might have
been better — been included in the NRC implementation regulation as should the
probability threshold for consideration of unlikely FEPs. (Comment 0368.5-4)
29.	The proposed rule would apparently preclude the NRC from taking into account any
corrosion of the waste package (or other engineered barriers) in the post-10,000 year
period, other than "general corrosion." See proposed 40 C.F.R. § 197.36 (c) (3). This is
based on EPA's apparent technical conclusion that other kinds of corrosion, for example
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localized corrosion, would not under any circumstances contribute to risk after 10,000
years. The Nuclear Waste Technical Review Board's June 2006 annual report to Congress
and DOE makes it clear that this conclusion has no scientific support. The Board advises
Congress and DOE that whether a combination of salts known to be present in Yucca
Mountain might cause localized corrosion in waste packages remains unanswered, and also
that stress corrosion cracking of engineered barriers cannot be dismissed based on the
current limited data. See Report at pp. 12-15. Given the scientific uncertainties cited by
the Board, there is no adequate basis for the proposition advanced by EPA that the effects
of localized corrosion and stress corrosion cracking will not be significant after 10,000
years. Thus EPA's proposed rule would unlawfully, and without sufficient scientific
support, preclude the NRC from taking significant unresolved safety issues into account in
its licensing decision. (Comment 0369-1)
30. The Board also raises questions in its June 2006 Report about the effectiveness of the
drip shields, which DOE plans to put in 50-300 years after closure, and for which DOE
takes credit in its safety calculations. The Board questions whether the drip shields along a
tunnel would stay connected in the event of an earthquake. If they do not remain
connected, then water could seep in and attack the waste packages. See Report at pp. 18-
20. EPA's proposed rule would apparently limit the NRC's consideration of seismic events
in the post-10,000 year period to "effects caused by damage to the drifts in the repository
and failure of the waste packages." While EPA does not define "waste package," the NRC
definition of the term seemingly does not include the drip shield. See 10 C.F.R. § 63.2
("Engineered barrier system means the waste packages, inclusing engineered components
and systems other than the waste package (e.g., drip shields)...." See also Fed. Reg.
55732, 55776, November 2, 2001. So, the combined effect of NRC's existing rules and
EPA's proposed rule would again be that the NRC would be precluded from taking a
significant unresolved safety issue into account in its licensing decision. (Comment 0369-
2)
Response to Issue A:
Two comments addressed concern about airborne pathways (Comments 0211.1-1 and
0315-1). From our examination of previous performance scenarios proposed for the
disposal system, we believe that in the post-closure period the ground-water pathway is the
only pathway through which radionuclides could reach the RMEI for the expected case.
Large amounts of airborne radionuclides would result from only a volcanic event; the
probability of eruptive volcanic events is very small, but is considered in the final rule as a
disruptive event that is to be considered in the performance assessments. (NAS Report p.
95)
Some comments expressed varying opinions on the probability limit we placed on FEP
inclusion or exclusion in disposal system performance assessments. Some comments
agreed with maintaining the probability limits from the 2001 rulemaking (Comments 0352-
9, 0352-11, 0217-2, and 0298-18), while some comments proposed that all scenarios,
regardless of probability, must be included in performance assessments (Comments 0226-
75, 0226-77, 0226-78, 0226-79, 0263-16, and 0369-1). We believe that the probability
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limits used in the 2001 rulemaking are still appropriate even though we have constructed a
compliance requirement for peak dose within the period of geologic stability. The previous
rulemaking required a post-10,000-year performance assessment, even though no
regulatory dose limit was applied to the results. Nevertheless, this requirement did not
allow the assessments to ignore important scenarios that would significantly affect
performance during the longer time frame. We believe the position we have taken in this
rulemaking is consistent with our previous intent and the NAS direction concerning peak
dose considerations. In light of the longer compliance period and the unavoidable
uncertainties it brings into the task of making very long-term dose projections, we believe
the probability limits are set to capture within the scenario development process a wide-
ranging set of FEPs that potentially could affect disposal system performance and provides
the foundation for a reasonable test of the disposal system.
Some comments argued that we are eliminating low-probability FEPs, even though they
could contribute to releases that would compromise the performance assessments
(Comments 0226-76, 0226-77, 0226-78, 0226-79, 0226-82, and 0263-16). We imposed
probability limits on the FEPs selection process to eliminate potentially endless speculation
on estimating exact probability numbers for very low-probability FEPs. The probability of
FEPs is determined by examining the geologic record around the site as well as the body of
technical information available from laboratory testing and real-world experience with
engineered materials. We believe that scientific judgment may be used in assigning
probabilities to FEPs, as well as evaluating their potential consequences under conditions at
the site over the compliance period. Requiring that any conceivable FEP and any
speculative prediction of its consequences be incorporated into the performance
assessments, we believe, would make it impossible to perform the analyses or interpret the
results sufficiently for regulatory decision-making, because of the unbounded speculation
involved. ICRP's 2007 recommendations also support our conclusion that the 10"8 annual
probability threshold presents a significant challenge to characterize FEPs with some
degree of confidence, given the limits of today's science and technology, and will result in
a wide-ranging set of FEPs:
"The use of probability assessment is limited by the extent that unlikely
events can be forecast. In circumstances where accidents can occur as a
result of a wide spectrum of initiating events, caution should be exercised
over any estimate of overall probabilities because of the serious uncertainty
of predicting the existence of all the unlikely initiating events. In many
circumstances, more information can be obtained for decision-making
purposes by considering the probability of occurrence and the resultant
doses separately."
(ICRP Publication 103, Docket EPA-HQ-OAR-2005-0083-0423, Paragraph 269. The term
"accidents" in the quotation above also refers to releases that occur far into the future, i.e.,
releases from the disposal system).
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Overall, we believe events with an annual probability lower than 10"8 would introduce
speculation beyond what is appropriate to define a reasonable test of disposal system
performance.
Further, in response to Comments 0226-75 and 0263-16, NAS itself suggested situations in
which scenarios need not be quantified. NAS discusses, in the context of volcanism, a 10"8
annual probability of occurrence as a level that "might be sufficiently low to constitute a
negligible risk" below which "it might not be necessary to consider" how the event might
contribute to releases from the disposal system. (NAS Report p. 95) We believe this
example is instructive, given that volcanism is the single scenario resulting in direct release
of radioactive material from the repository into the biosphere, resulting in relatively
immediate exposures. We believe it is reasonable to extend the concept expressed by NAS
as "negligible risk" to FEPs whose influences are seen in the gradual release and transport
of radionuclides over long periods of time. Therefore, we believe that lowering the
probability threshold, or eliminating it altogether, would be inconsistent with the important
NAS cautions to focus assessment efforts on FEPs that can be bounded within the limits of
geologic stability. As a result, we believe that the probability limits we have established,
and implemented in other applications of geologic disposal, are scientifically rigorous and
consistent with a protective approach.
One commenter offered a simple example of the effects on dose calculations of excluding
some scenarios (Comments 0226-76 and 0226-77). While the example is illustrative of the
point about the possible effects of excluding some scenarios, the probabilities used in the
example are equal to or significantly higher than those proposed in the rule - all these
processes would be included, so the answer is not representative of the actual effect of
excluding low-probability FEPs. In addition, the example is misleading in its simplified
calculation. The elimination of a FEP on the basis of consequence would be based upon its
effect on the overall results of the aggregation of scenarios, each of which includes multiple
FEPs that make up the performance assessment. A FEP would not be eliminated on the
basis of probability if its probability were as high as shown in the example. Another
perspective on the consideration of low probability FEPs is the issue of uncertainties in
performance due to expected variations in the major "driver" processes and the associated
parameters in the performance assessments contrasted with the effects of low probability
FEPs. If the variation of calculated doses from the major processes controlling dose
extends over an order of magnitude or more, for example, a dose variation of only a percent
or two due to the inclusion of a low probability FEP in question would be inconsequential
in magnitude and not discernable within the variations due to other processes.
One comment (Comment 0352-12) proposed that FEPs whose effect could not be measured
without accelerated testing should be eliminated from consideration in performance
assessments. We disagree with this suggestion in that many important processes in the
post-closure time frame cannot be quantified without some form of "accelerated" testing.
For example, corrosion testing is usually done in an accelerated fashion to simulate in the
laboratory in days to weeks what the actual in-service performance would be over much
longer periods. We are aware of the limitations of such testing in terms of applying them
in performance assessments and interpreting the results. One comment (Comment 0209.7-
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4) also proposed that there may be earlier release scenarios than those resulting from
failures caused by corrosion, but did not describe any of the scenarios alluded to in the
comment. We cannot evaluate this comment further without additional explanation, but we
believe the commenter should send any additional explanation to either the DOE or NRC
for consideration in their efforts on safety assessment for the repository.
On a similar point, several comments characterized our proposal as assuming that no
manufacturing defects will exist in the waste packages or that we are excluding the effects
of localized corrosion from the analyses and preventing NRC from considering this process
(Comments 0226-80, 0324-33, 0362.1-1, and 0365-1). On the contrary, our proposal
makes no assumptions about the quality of construction or durability of the waste packages.
Our standards provide the appropriate protections in the initial 10,000-year period, when
such defects might result in releases earlier than expected. Should significant releases be
projected to occur shortly after 10,000 years, NRC has stated (EPA-HQ-OAR-2005-0083-
0376, p.49) that it would take such trends into account in its licensing decision, even if the
standards beyond 10,000 years were not exceeded. We believe our peak dose standard
appropriately considers the factors involved in conducting performance assessments
covering the period up to 1 million years. Further, we are not limiting consideration of
localized corrosion. Comment 0362.1-1 interprets our statements in the proposal as
requiring that "the potential for significant new effects.. .must be ignored unless they can
be shown to be significant before" 10,000 years. This is not the case. We explicitly
recognized localized corrosion as a process that would operate during the early period of
disposal, when temperature effects would be most significant (the commenter specifically
indicates the potential for localized corrosion at temperatures between 160 and 220 °C, or
about 320 and 430 °F). We contrasted that with general corrosion in the sense that the
long-term effects of general corrosion are likely to be more significant to package failure.
However, localized corrosion must be considered for the entire compliance period if it is
included for the initial 10,000 years. It is unclear to what "significant new effects" from
long-term localized corrosion the commenter is referring, but we are not limiting NRC's
ability to examine the way that process is incorporated into the performance assessments.
DOE will have to defend its assumptions regarding waste package performance in its
license application.
These comments raise an important issue, which is the potential for FEPs, particularly
seismic and igneous events, to cause direct damage to the engineered barrier system (e.g.,
repository drifts, drip shields and waste packages). Regardless of other effects of these
events on the disposal system, the timing and degree of waste package degradation has a
significant effect on peak dose. The longevity of waste packages, when considering
periods of hundreds of thousands of years, is uncertain and dependent on a number of
factors. Therefore, the aspect of primary interest in evaluating seismic and igneous FEPs is
their potential to breach waste packages and make radioactive material available for
transport by infiltrating water (or, in the case of volcanic events, for direct release into the
biosphere).
Comments 0226-80, 0226-83, 0362.1-1, and 0365-1 criticize our approach to exclude FEPs
on the basis of their significance to the performance assessment results. We recognize that
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setting forth the significance screening criterion in §197.36(a) of our proposal as pertaining
to the 10,000-year period could be construed as creating a situation in which important
long-term processes could be excluded altogether from the analysis if they were not
significant in the earlier period. However, we do not believe it is reasonable to interpret the
significance criterion in this way. We have taken specific steps to ensure that significant
long-term FEPs will be considered in the assessments. Consistent with NAS, we have
addressed the long-term effects of seismic, igneous, and climatic FEPs. In addition, as
described below, we have directed that the effects of general corrosion on the barrier
system be evaluated. Further, contrary to some comments, we explicitly required that FEPs
included in the 10,000-year analysis must continue to be included for the longer-term
(10,000 years to 1 million years) assessment. That is, FEPs included in the initial 10,000-
year assessments will continue to operate throughout the period of geologic stability.
These FEPs are already identified as appropriate for inclusion, and include fundamental
physical and geologic processes that play roles in the release and transport of radionuclides,
regardless of the time period covered by the assessment.
As noted above, to further bolster the significance screening criterion, in our proposal we
considered whether some FEPs eliminated from consideration during the first 10,000 years
should be included in the longer-term assessment if they would have a significant bearing
on performance at later times, even if they could legitimately be dismissed for the initial
10,000-year period. We focused our attention on FEPs affecting the engineered barriers
since, as noted above, waste package failure is the dominant factor in the timing and
magnitude of the peak dose, and is the primary reason for considering time frames up to 1
million years. To illustrate one consideration, thermal conditions in the repository change
dramatically within the initial 10,000-year period, affecting the relative importance of some
FEPs during and after the thermal pulse. However, FEPs involved in release and transport
of radionuclides would generally be the same, regardless of when the waste package fails.
Further, while FEPs associated with the natural characteristics of the site are active today or
can be observed in the geologic record, FEPs related to engineered barrier longevity
involve extrapolation of shorter-term testing data. The degree to which natural FEPs can
contribute to the breaching of waste packages is dependent to a large extent on the
condition of those packages over time, making FEPs specific to the engineered barriers of
particular importance. We took this approach for two reasons. First, we needed to clearly
outline the reasons why a FEP that could be excluded on the basis of significance from the
performance assessments for the initial 10,000-year period might potentially need to be re-
considered for the lengthened compliance period. Second, we wanted to further our goal of
issuing an implementable standard by eliminating potentially unconstrained speculation
over the longer compliance period. By discussing the considerations involved in evaluating
FEPs that could be previously excluded, we hoped to lay out clearly the reasoning that
could be used to justify inclusion of additional FEPs beyond those identified by the NAS
committee.
We explicitly addressed general corrosion of the waste packages and engineered barriers in
our proposal because it is likely to be a significant degradation process at later times. This
FEP is significant at times greater than 10,000 years because we believe it is the principal
process FEP that could lead to "gross breaching" of the waste package over those extended
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time frames. Processes and events that could lead to "gross breaching" are of greatest
significance to long term performance because, as noted by the NAS, "canisters are likely
to fail initially at small local openings through which water might enter, but out of which
the diffusion of dissolved wastes will be slow until the canister is grossly breached." (NAS
Report p. 86) It is the time of "gross breaching" that determines the time of more rapid
release of dissolved wastes from the repository and hence may have a significant effect on
the time and magnitude of the peak dose within 1 million years. Although the general
corrosion process is slow, tends to decrease with decreasing temperature, and may not lead
to significant releases for the first 10,000 years (depending on DOE's design of the waste
package), we believe this FEP is significant enough over the long term to require inclusion
in the assessment of performance during the time of geologic stability, regardless of the
screening decision in the first 10,000 years. Further, consideration of the uncertainties
involved in extrapolating general corrosion data for the proposed waste package materials
supports the inclusion of this potentially highly significant process ("Assumptions,
Conservatisms, and Uncertainties in Yucca Mountain Performance Assessments," Docket
No. EPA-HQ-OAR-2005-0083-0085, Section 5.4.1). Therefore, we believe that general
corrosion, as well as those FEPs related to seismicity, igneous activity and climate change
identified by NAS, require explicit inclusion in the assessments during the time of geologic
stability. In fact, general corrosion is a process that will take place from the time of
repository closure onwards and would be included by the probability screen and included
based on its consequences over the very long term.
We did, as Comment 0226-73 pointed out, consider providing NRC more latitude to
identify FEPs if they would significantly affect the peak dose. We view the requirement to
include general corrosion, as well as the climate, seismic, and igneous scenarios identified
by NAS, as leading to an effective and extensive assessment, which can fairly be
represented as a reasonable test of the disposal system. As we discussed in our proposal,
the search for additional FEPs that might be argued as significant at some point beyond
10,000 years can rapidly become highly speculative and bounded largely by the limits of
the imagination and of limited in benefit if the speculation cannot be removed. Therefore,
we continue to believe that our approach represents "informed judgment" and a reasonable
test of repository performance over time frames as long as 1 million years.
Most commenters who disagreed with our proposal cited the limited data available on
various corrosion mechanisms that could affect the waste packages (e.g., Comments
0362.1-1, 0365-1, and 0369-1). Many of these commenters seem to believe that we have
excluded all corrosion mechanisms except general corrosion. This is not the case. We
have explicitly directed that general corrosion be considered because it is likely to be the
most significant such process at longer times; however, other corrosion mechanisms (such
as localized corrosion) are more likely in the early period after disposal when temperatures
inside the repository are high. For example, Comment 0369-1 cites the Nuclear Waste
Technical Review Board (NWTRB) as concluding "that stress corrosion cracking of
engineered barriers cannot be dismissed based on the current limited data." The NWTRB
states in its June 2006 Report to the U.S. Congress and Secretary of Energy: "Alloy-22 has
been shown to be very resistant to, but not immune from, SCC under many Yucca
Mountain conditions at temperatures below approximately 160°C. Although Alloy-22 can
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exhibit SCC under these conditions, very high stress intensities induced by pre-cracking are
required, and even then cracks propagate very slowly. However, for Yucca Mountain
environments above about 160°C, only limited SCC data exist for Alloy-22. Given that the
susceptibility of metals to SCC generally increases with temperature, the Project will have
to obtain relevant data under higher-temperature conditions, assume that SCC will occur, or
use a different approach." (Docket No. EPA-HQ-OAR-2005-0083-0395) If DOE
determines these processes to be insignificant within 10,000 years, when thermal effects
are at their highest, they are not likely to be more significant than general corrosion at later
times. If they are included in the 10,000-year analysis, they must be included in the longer-
term assessments.
Comment 0226-80 highlights our discussion of criticality as excluding one of the "most
worrisome threats to the repository" over the long term. We cited an NRC technical study
to support our conclusion that such an event is unlikely to be significant to the results of the
assessments (70 FR 49054). Further, the DOE reference cited above concludes that all
criticality scenarios fall below the probability screening threshold. We do not believe it is
necessary to specify that criticality be evaluated.
Comment 0369-2 again cites the NWTRB in charging that we have "precluded NRC from
taking a significant unresolved safety issue into account in its licensing decision" by
limiting the scope of seismic analyses beyond 10,000 years to "effects caused by damage to
the drifts in the repository and failure of the waste packages." The commenter views this
as excluding the potential for displacement of drip shields through ground motion, an issue
raised in NWTRB meetings. The commenter correctly notes that drip shields are not part
of the waste package. However, we do not view the "drifts in the repository" as being
limited to the emplacement tunnels themselves. We consider that this provision also
applies to the loss of functionality of structural components of the engineered barriers,
including the drip shields and the inverts supporting the waste packages. Effects of seismic
events on the drip shields could include both physical damage (e.g., through rockfall) and
loss of function without physical damage through displacement. Displacement could allow
water to contact the waste packages and contribute to waste package failure. The June
2006 NWTRB report indicates that DOE has evaluated this possibility (Docket EPA-HQ-
OAR-2005-0083-0395, p. 19).
An alternative view on our FEPs screening process was expressed in a report by the
Electric Power Research Institute (EPRI): "Thus, the current EPA screening limit is very
conservative compared to the [Negligible Incremental Dose] level suggested by [NAS], It
is likely that there are many FEPs that DOE has already included in their analysis using the
EPA approach that would not have been included if the [NAS]-recommended approach had
been followed. Given that many additional FEPs are already included, it should be
unnecessary to include any additional FEPs if the regulatory compliance period is extended
beyond 10,000 years." ("Yucca Mountain Licensing Standard Options for Very Long Time
Frames," April 2005, pp. 3-5 and 3-6, Docket No. EPA-HQ-OAR-2005-0083-0087)
Taking all of this information into account, we continue to believe that our approach to
assigning probabilities to FEPs and the screening process is sufficiently rigorous to capture
all the pertinent FEPs for a reasonable test of the disposal system performance over the
compliance period.
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Comment 0331-10 made the argument that human intrusion should be included in the
naturally occurring events. For the Yucca Mountain standards, the NAS specifically
recommended that the treatment of human intrusion be addressed stylistically and
evaluated separately from the post-closure performance assessment for the individual-
protection standard (NAS Report p. 104), therefore, we have remained consistent with the
NAS recommendation for treatment of intrusion as the compliance period has been
extended. NAS concluded that institutional controls could not eliminate the possibility of
human intrusion, nor could the probability of intrusion be predicted. NAS therefore
recommended that the intrusion be assumed to occur (i.e., assigned a probability of one).
(NAS Report pp. 11-12)
Comments 0368.5-4 and 0217-2 expressed agreement with the specifications for FEPs
described in the proposal, in terms of their substantive merits, but expressed an opinion that
NRC is the authority that should make these stipulations for the treatment of FEPs in the
safety assessments. We believe that NRC will critically evaluate the manner in which DOE
performance assessments treat FEPs in the analyses and make any alternative treatments
they deem appropriate to evaluate the projected performance of the disposal system.
Section 16 FEPs and Screening Criteria
Issue B: Seismic FEPs
1.	EPA proposes that only seismic effects on the engineered barriers should be considered.
While conceding that seismic events also could affect the natural system— particularly by
affecting fluid transport pathways—EPA is "proposing that DOE's analysis for seismic
events may exclude the effects of seismicity on the hydrology of the Yucca Mountain
disposal site." 70 FR 49056. EPA based this exclusion on two rationales: first, that
predicting alterations in flow would be "highly speculative," and second, that any effects of
seismic events would be overshadowed by the effects of climate change. (Comment 0226-
85)
2.	These rationales are wholly inconsistent with the NAS's determinations. Rather than
suggesting that seismic effects on hydrology could be excluded from analysis, NAS wrote
that "[w]ith respect to the effects of seismicity on the hydrologic regime, the possibility of
adverse effects due to displacements along existing fractures cannot be overlooked." NAS
Report at 93 (emphasis added). NAS did also state, as EPA selectively notes, that favorable
alterations in the hydrologic regime were possible, but then went on to conclude that "the
consequences of these events are boundable for the purpose of assessing repository
performance." Id. But NAS never qualified its admonition that seismic effects on
hydrology "cannot be overlooked" by suggesting, as EPA does now, that climate change
might have similar but larger effects. That rationale is patently flawed, for it overlooks the
realistic possibility that adverse hydrologic effects arising from seismic events would
compound the adverse effects of climate change; there is no reason to assume that adverse
climate change effects would preclude adverse seismic effects from occurring. (Comment
0226-86)
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Response to Issue B:
After considering public comments, we are adding a provision to address a potential effect
of seismicity on hydrology that was identified by NAS. The final rule now requires DOE
to assess the potential effects of changes in the ground-water table as a result of seismicity.
We noted in our proposal (70 FR 49055-49056) the NAS statement that "[w]ith respect to
the effects of seismicity on the hydrologic regime, the possibility of adverse effects due to
displacements along existing fractures cannot be overlooked" but that "such displacements
have an equal probability of favorably changing the hydrologic regime." (NAS Report p.
93) We argued that these effects would likely be minimal given the many small-scale
changes that would be possible in the connectivity of the fracture networks, and that these
effects would likely be small compared to the effects of climate change on the hydrologic
behavior of the disposal system. We did not mean to imply that the seismic and climate
events would involve the same hydrologic characteristics and processes or produce the
same effects on the ground-water flow regime, but that the effects of one were likely to
outweigh the effects of the other. While we still believe that is likely, we have concluded,
after further consideration, that the issue of hydrologic effects resulting from seismic events
needs to be examined in sufficient detail to address the point made by NAS. We believe
the effects of fault displacement on the hydrologic regime will be adequately addressed by
the variation in parameters such as hydraulic conductivity (i.e., evaluating reasonable
variation in ground-water flow parameters, whether seismically-induced or not, will
illustrate the range of effects that might result from seismicity). However, NAS also
identified another seismic effect on hydrology, namely the potential for transient rise in the
ground-water table. In this instance, NAS did not simply state that such potential could be
bounded, but noted site-specific studies suggesting that such a rise would be "on the order
of 20 m or less" (NAS Report p. 94). Therefore, the final rule requires the potential effects
of a rise in the ground-water table as a result of seismicity to be considered. NRC may
determine the magnitude of the elevation of the water table rise and its significance on the
results of the performance assessment, or NRC may require DOE to demonstrate the
magnitude of the elevation of the water table rise and its significance during licensing. If
NRC determines such effects to be significant to the results of the performance assessment,
it shall specify the extent of the rise for DOE to assess.
We believe deferring to NRC on this point is the appropriate approach. The above quote
from page 94 of the NAS Report makes it clear that changes to the hydrologic regime from
seismic events would be equally likely to enhance or reduce transport of radionuclides.
However, we believe these seismically induced changes are likely to be approximated by
the normal variation in flow parameters. It may be that changes in the hydrologic system
from climate change, including elevation of the ground-water table, may be quantitatively
more significant than such changes resulting from seismic activity. We believe NRC is
better positioned to make judgments regarding the extent of such changes. We note that a
dozen years of site characterization, scientific study, and performance assessments have
been conducted since the NAS Report in 1995. NRC has conducted its own analyses as
well as participated in ongoing technical exchanges with DOE over this period. We view
deferring to NRC's judgment in this case as comparable to the approach we have taken
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with climate change. In that instance, we outlined the primary issues and overall approach,
but specified that NRC would establish the details required to implement our standard.
Section 16 FEPs and Screening Criteria
Issue C: Volcanism and igneous events
1.	Lincoln County agrees with EPA's proposal to require DOE to consider the exposure
consequences of igneous events during the 10,001 to 1,000,000 regulatory compliance
periods. Further, EPA's proposal to limit said analyses to volcanic events that intersect the
repository, damage the waste packages, and cause releases of radionuclides either directly
to the atmosphere and biosphere or to the groundwater appears reasonable. (Comment
0219-4)
2.	EPA states that DOE need only consider as FEPs volcanic events that have occurred, or
may reasonably be inferred to have occurred, during the Quaternary Period, which includes
approximately the last 1.6 million years. 70 FR 49052. The rationale, apparently, is that if
events haven't occurred during the last 1.6 million years, the probability of their occurrence
within the next million years is negligible. For events likely to occur on a shorter time cycle
(e.g. climate shifts), this might be a reasonable assumption, since a 1.6 million-year period
is long enough to encompass numerous climate cycles and provide a sense of the full range
of possibilities. Volcanic eruptions in the Yucca Mountain area, however, occur
infrequently and irregularly, and the activity in one 1.6-million year period—a long period
by human standards, but a short one for many geologic processes—may not be an accurate
preview of future activity. To assume that the volcanic events of the next million years are
bounded by the events of the previous 1.6 million years is somewhat like assuming that
Chicago's weather tomorrow can be predicted, with certainty, by reviewing the weather
reports from the previous two days. (Comment 0226-89)
3.	EPA's own consultant's report concedes that during the Pliocene Epoch (5.2 million
years before present to 1.6 million years before present), several larger-scale eruptions
occurred at the site. Cohen Report at 10-1 to 10-2. Moreover, EPA's own rule
acknowledges that the type of eruptions that formed the tuffs at Yucca Mountain is not the
same as the type of eruptions that are known to have occurred more recently. EPA at 70 FR
49058. The difference is important; in comparison to most basaltic eruptions, the eruptions
that produce welded tuffs generally are gigantic. (Comment 0226-90)
4.	In requiring that DOE model only events that occurred during the Quaternary period,
EPA is excluding possible volcanic events from analysis. Moreover, it isn't excluding just
any events, but instead is selectively leaving out larger events. While such events have low
probabilities, since volcanic events in the region are infrequent, their effects, if they do
occur, could be major, and there is no foundation for EPA's rationale for screening them
out entirely. (Comment 0226-91)
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5.	White Pine County agrees with EPA's proposal to require DOE to consider the exposure
consequences of igneous events during the 10,001 to 1,000,000 regulatory compliance
period. Further, EPA's proposal to limit said analyses to volcanic events that intersect the
repository, damage the waste packages, and cause releases of radionuclides either directly
to the atmosphere and biosphere or to the groundwater appears reasonable. (Comment
0315-4)
6.	Section 197 .12: The duration of geologic stability is at best guesswork, although the
presence of comparatively recent volcanic activity and record of seismic activity in the
vicinity of Yucca Mountain should receive heavy weighting in the analysis. (Comment
0331-11)
7.	We wish to call EPA's attention to a possible drafting problem. Proposed 40 C .F.R. §
197.36 (c) (1) (ii) states that the "igneous event may be limited to that causing damage to
the waste packages directly . . . ." This might (but need not) be read to preclude
consideration of any igneous events that are projected to occur after waste package failure.
We assume no such interpretation was intended since the preamble has no discussion that
could serve to justify the exclusion of such a large category of potentially significant
events. (Comment 0357-3; 359-3)
Response to Issue C:
First, in order to prevent confusion, we will provide some definitions of the major terms we
use in this response. The Pliocene Epoch was a subdivision of geological time from
approximately 5.3 million years ago to approximately 2 million years ago. (Source:
University of California, Berkeley, ( http://www.ucmp.berkelev.edu/tertiarv/pli.html ). The
Quaternary Period is a subdivision of geological time which covers the last two million
years up to the present day. (The exact duration is a matter of debate with estimates of the
onset of the Quaternary Period placed between 1.8 million years and 2.6 million years ago
by different authors) The Quaternary can be subdivided into two epochs; the Pleistocene
(two million years to ten thousand years ago) and the Holocene (ten thousand years ago to
the present day) (Source: Quaternary Research Association, http://qra.org.uk/what.html).
EPA agrees with the commenter (0226-90) who states that evidence of past volcanic events
in the Pliocene Epoch should also be considered in determining the probability of igneous
FEPs for performance of the repository out to 1 million years. As we stated in the
preamble to the proposal (70 FR 49056), we agreed with NAS that the probability of
igneous events may be great enough, and the potential consequences significant enough,
that they must be considered over the period of geologic stability.
Concerning which events to consider for the igneous FEPs, we looked at the geologic
record of the area. Over the past 11 million years there has been a shift in the types of
igneous events that have taken place in the Yucca Mountain vicinity. The repository block
tuffs are in the age range of approximately 11-12 million years old and were generated by
the large-scale volcanism mentioned by the commenter (0226-90), and involved a large
area around the site. Information compiled by the NRC (ACNW Meeting, 2004, Docket
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No. EPA-HQ-OAR-2005-0083-0373, 0378) concerning basaltic igneous activity around
the site shows that this type of activity has been the only activity around the site through
the Pliocene, and that volume of eruptive activity (both tuff and basaltic material) has
decreased continually over the last ten million years (Compton et al., 2004, Docket No.
EPA-HQ-OAR-2005-0083-0377). From the identification of surface as well as indicators
of buried remnants of past volcanic activity, the episodes of basaltic activity around the site
can be shown to have occurred in clusters of events around one million and four million
years ago (Hill, 2004 Docket No. EPA-HQ-OAR-2005-0083-0373). The occurrence of
these clusters indicates that the nature and extent of past volcanic activity can be
reasonably well characterized and that annual probabilities for such events can be
reasonably estimated from the geologic record around the site. Annual probabilities of
volcanic disruptions of the repository have been estimated by various workers, and range
from as high as 10~6 to as low as 5.4 x 10"10 (Compton, et. al, 2004, Docket No.EPA-HQ-
OAR-2005-0083-0377). These probabilities fall across the 10"8 probability cut-off limit
and indicate that intrusions of this type would have to be considered in DOE's performance
assessments. The site evidence and history of volcanic activity indicate that the nature of
this potentially disruptive event can be reasonably characterized both in terms of
probability and consequences for repository performance, based on the number of events
that have occurred in the past.
Basalt volcanism, exemplified by the Lathrop Wells scoria cone, and other features near the
repository, appears to be the type of igneous activity, though unlikely, that has some
probability of occurring within the period of geologic stability. By specifying a probability
threshold, we focus the analysis on the type of events most plausible during the period of
geologic stability. Statements made by the commenter (0226-90) in which it was suggested
that DOE consider eruptions that produce welded tuffs (of the type produced 11-12 million
years ago) which "generally are gigantic" shows a lack of understanding for the concept of
geologic stability as it pertains to performance assessment. Volcanic events as large as the
ones that produced the Yucca Mountain area can change the landscape entirely and create a
situation in which site characteristics could be far different from those seen today. For time
periods where conditions at the site would change dramatically in a relatively short time,
projections of site conditions would be highly speculative, and consequently performance
assessments would have very limited if any validity. It would be unreasonable to require
any repository to be designed to withstand catastrophic events having such far-reaching
consequences. The potential for such large-scale events would more appropriately be
addressed during site selection.
It is important to understand that "stable" in this context is not synonymous with "static and
unchanging." Rather, NAS recognized that many "physical and geologic processes" are
characteristic of any site and have the potential to affect performance of the disposal
system. NAS concluded that these processes could be evaluated as long as "the geologic
system is relatively stable and varies in a boundable manner" (NAS Report p. 9). Thus, the
site itself could be anticipated to change over time, but in relatively narrow ways that can
be defined ("bounded"). Implicit in the NAS recommendation is the idea that the
maximum risk might occur outside the period of geologic stability, but assessments
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performed at that time would have little credibility and would not be a legitimate basis for
regulatory decisions: "After the geologic environment has changed, of course, the scientific
basis for performance assessment is substantially eroded and little useful information can
be developed." (NAS Report p. 72).
Comments 0357-3; 359-3 state that our proposal states that the "igneous event may be
limited to that causing damage to the waste packages directly . . . ." This might (but need
not) be read to preclude consideration of any igneous events that are projected to occur
after waste package failure." The comments are correct, and we did not assume such an
interpretation. We note that NRC has defined "waste package" to include the waste form
(10 CFR 63.2), which is not inconsistent with our intent.
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Section 17 Reasonable Expectation/Implementabilitv
1. However, if my interpretation of language in the Proposed Rule is correct, I basically
disagree with how EPA has attempted to incorporate the concept of "reasonable
expectation" into regulations for Yucca Mountain. On the basis of discussions in the
Supplementary Information, language in the Proposed Rule, and language in other parts of
40 CFR Part 197 that are not subject to change in the Proposed Rule, it seems to me that
the only way EPA has incorporated the concept of "reasonable expectation" in these
regulations is by specifying that the mean or median of probability distributions of
projected doses must not exceed specified dose criteria .The description of "reasonable
expectation" in § 197 .14 notwithstanding, I do not see any other way that "reasonable
expectation" is incorporated in the regulations in regard to how that concept can be used by
the NRC in evaluating DOE's license application for Yucca Mountain.
.. It seems to me that a reasonable interpretation of the proposed wording in the
regulations noted above [§ 197.13, § 197.20, and § 197.25] is that NRC must render its
licensing decision on the basis of objective comparisons of means or medians of probability
distributions of calculated doses with specified dose criteria, even though the standard of
proof of compliance is one of "reasonable expectation." If my interpretation is correct, the
wording in the regulations indicates to me that EPA has misinterpreted the concept of
"reasonable expectation" and applied it inappropriately.
The basic idea behind the concept of "reasonable expectation" is that decisions ...
cannot be based solely on objective comparisons of results of performance assessment...
with specified numerical criteria (e.g., a limit on dose). Rather, the concept of "reasonable
expectation" requires that licensing authorities exercise subjective scientific judgment...
the essential point being that subjective scientific judgment necessarily involves important
qualitative considerations that are not captured in quantitative probability distributions of
projected doses. Indeed, discussions in the Supplementary Information concerning
"reasonable expectation" and the importance of uncertainties at far future times emphasize
that regulatory decision making over time frames out to one million years involves
important qualitative considerations. However, it appears that EPA has not properly
accounted for this essential aspect of the concept of "reasonable expectation" in
formulating its decision rules concerning compliance with dose criteria in these regulations.
The essence of my concern boils down to two simple questions that EPA must
clearly address in developing its regulations for Yucca Mountain:
•	Is NRC required to reject a license application if means or medians of probability
distributions of projected doses exceed specified dose criteria, without regard for
any other considerations?
•	Is NRC required to issue a license if means or medians of probability distributions
of projected doses do not exceed specified dose criteria, without regard for any
other considerations?
If the answer to both of these questions is "yes," then EPA has improperly applied the
concept of "reasonable expectation" in formulating its decision rules in the regulations. If
the answer to both of these questions is "no," then EPA has recognized what "reasonable
expectation" means and how it should be applied in regulatory decision making, but what is
missing from the regulations is some discussion of conditions under which NRC can reject
a license application if specified dose criteria appear to be met or issue a license if not. I
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appreciate that specificity about such conditions is inappropriate, but the basic idea must be
clearly stated.
The essential point of these comments is that NRC must have the flexibility to
evaluate the totality of information in deciding whether or not to license the Yucca
Mountain facility. For example, NRC must be allowed to reject a license application that
indicates compliance with specified dose criteria if, in NRC's judgment, important factors
that could lead to substantially higher projected doses have not been properly accounted for
in DOE's performance assessment that supports the license application. Conversely, NRC
must be allowed to license the facility, even though a license application may indicate
noncompliance with specified dose criteria under some conditions, if, in NRC's judgment,
assumptions in performance assessments that led to an appearance of noncompliance are
not credible. Thus, the regulations must be written in such a way that these kinds of
decisions by NRC clearly are allowed. I do not believe that EPA's proposed wording in the
regulations meets this crucial test. (Comment 0186-6)
2.	Requiring absolute assurance of dose rates less than a tiny fraction of natural
background, even for only a small number of people, over a timeframe extending from
10,000 to a million years, is not only infeasible, but it is indefensible and completely
inconsistent with all other environmental regulations ever promulgated. (Comment 0201-2)